ClickFix attack pushes macOS infostealer for crypto theft attacks

ClickFix-style attacks are being used to deliver a Go-based malware capable of stealing cryptocurrency assets, as well as browser-stored passwords, Apple iCloud Keychain data, and cached credentials. The macOS-focused infection chain is designed to deliver a shell script that profiles the host and then fetches a macOS malware payload that's compatible with the computer's CPU architecture. "While the malware payload is capable of stealing passwords, its most interesting function is its capability to slowly deplete cryptocurrency accounts, siphoning their contents into accounts under the threat actor's control," Huntress security researcher Andrew Brandt said. The attack chain begins with pasting a ClickFix command into the Terminal app, triggering the execution of a Bash profiler/loader that collects extensive system details and then retrieves a Mach-O payload that matches the victim's processor architecture. The payload is a Go-based stealer that can capture browser passwords, Apple Keychain data, and cached credentials and transmit them to a remote server operated by the threat actor. Like other macOS stealers, the malware attempts to escalate privileges by prompting the victim to enter their system credentials via a fake prompt under the guise of an "unexpected system error" and restoring damaged system files. What's notable about the malware is that it also packs in a "DRAIN" routine that checks if a cryptocurrency wallet holds funds, and if so, redirects a chunk or all of it to an attacker-controlled wallet. There exist multiple versions of the same function based on the cryptocurrency being targeted. This includes Bitcoin, Litecoin, Dogecoin, Monero, Ethereum, and Ripple's XRP. "While this may not be a brand new feature, it's the first time we have seen malware capable of emptying a cryptocurrency wallet that could be used to remove any less than the entire wallet's value," Huntress said. "The malware contained separate functions to determine just how much 1% of the wallet's contents is worth, depending on which cryptocurrency the malware targets." The server staging the malicious payloads and the command-and-control (C2) server all link back to infrastructure belonging to Aeza Group, a Russian bulletproof hosting provider that has been sanctioned by the U.S., the U.K., and Australia for facilitating bad actors. The disclosure comes as a number of ClickFix attacks have been reported in recent weeks - A macOS ClickFix campaign distributing MacSync and Atomic Stealer malware that uses a cluster of look-alike domains and implements a server-side browser-fingerprinting and hardware validation gate to conditionally serve the lures only to those visitors whose environment appears consistent with a genuine macOS browser, while blocking crawlers, sandboxes, and some automated analysis tools. A ClickFix variant that abuses Program Compatibility Assistant ("pcalua.exe"), a legitimate Windows binary, as a launcher to bypass parent-process heuristics. "The victim is tricked (via a ClickFix lure) into pasting a crafted command that spawns PowerShell, uses WMI to create cmd.exe, mounts a remote WebDAV share, and loads a malicious DLL through rundll32.exe," Palo Alto Networks Unit 42 said. "The WebDAV share is exposed over HTTPS via CDN-fronted infrastructure at a per-victim tokenized URL (UUIDv4 path) used to deliver malicious DLL. Once loaded, the DLL is leveraged to deploy infostealer capabilities on the compromised host." A ClickFix campaign that uses on-the-fly WebAssembly (wasm) module instantiation and steganography through SVG images to evade network-level detection. The activity uses legitimate-but-compromised websites to run injected malicious JavaScript that builds a wasm module that exports URLs from which the SVG files are downloaded to construct the ClickFix URL. "This final ClickFix URL is then dropped onto the DOM with a script tag to display the fake verification page," Unit 42 said. "The fake verification page presents a checkbox. When the checkbox is clicked, the page presents instructions to paste content into a Run window." The findings also coincide with the discovery of two other stealer campaigns, one which delivers Lumma Stealer via files disguised as 1080p WEBRip and Blu-ray releases of The Odyssey, a newly released movie adaptation of Homer's ancient Greek epic poem of the same name, and another which uses cracked software and pirated game lures hosted on fake websites via SEO poisoning to drop Remus, a 64-bit variant of Lumma Stealer.

Cybersecurity researchers are calling attention to a nefarious campaign targeting WordPress sites to make malicious JavaScript injections that are designed to redirect users to sketchy sites. "Site visitors get injected content that was drive-by malware like fake Cloudflare verification," Sucuri researcher Puja Srivastava said in an analysis published last week. The website security company said it began an investigation after one of its customer's WordPress sites served suspicious third-party JavaScript to site visitors, ultimately finding that the attackers introduced malicious modifications to a theme-related file ("functions.php"). The code inserted into "functions.php" incorporates references to Google Ads, likely in an attempt to evade detection. But, in reality, it functions as a remote loader by sending an HTTP POST request to the domain "brazilc[.]com," which, in turn, responds with a dynamic payload that includes two components - A JavaScript file hosted on a remote server ("porsasystem[.]com"), which, as of writing, has been referenced on 17 websites and contains code to perform site redirects A piece of JavaScript code that creates a hidden, 1x1 pixel iframe, within which it injects code that mimics legitimate Cloudflare assets like "cdn-cgi/challenge-platform/scripts/jsd/main.js" – an API that's a core part of its bot detection and challenge platform It's worth noting that the domain "porsasystem[.]com" has been flagged as part of a traffic distribution system (TDS) called Kongtuke (aka 404 TDS, Chaya_002, LandUpdate808, and TAG-124). According to information shared by an account named "monitorsg" on Mastodon on September 19, 2025, the infection chain starts with users visiting a compromised site, resulting in the execution of "porsasystem[.]com/6m9x.js," which then leads to "porsasystem[.]com/js.php" to eventually take the victims to ClickFix-style pages for malware distribution. The findings illustrate the need for securing WordPress sites and ensuring that plugins, themes, and website software are kept up-to-date, enforcing strong passwords, scanning the sites for anomalies and unexpected administrator accounts created for maintaining persistent access even after the malware is detected and removed. Create ClickFix Pages Using IUAM ClickFix Generator The disclosure comes as Palo Alto Networks Unit 42 detailed a phishing kit named IUAM ClickFix Generator that allows attackers to infect users with malware by leveraging the ClickFix social engineering technique and come up with customizable landing pages by mimicking browser verification challenges often used to block automated traffic. "This tool allows threat actors to create highly customizable phishing pages that mimic the challenge-response behavior of a browser verification page commonly deployed by Content Delivery Networks (CDNs) and cloud security providers to defend against automated threats," security researcher Amer Elsad said. "The spoofed interface is designed to appear legitimate to victims, increasing the effectiveness of the lure." The bespoke phishing pages also come with capabilities to manipulate the clipboard, a crucial step in the ClickFix attack, as well as detect the operating system used in order to tailor the infection sequence and serve compatible malware. In at least two different cases, threat actors have been detected using pages generated using the kit to deploy information stealers such as DeerStealer and Odyssey Stealer, the latter of which is designed to target Apple macOS systems. The emergence of the IUAM ClickFix Generator adds to a prior alert from Microsoft warning of a rise in commercial ClickFix builders on underground forums since late 2024. Another notable example of a phishing kit that has integrated the offering is Impact Solutions. "The kits offer creation of landing pages with a variety of available lures, including Cloudflare," Microsoft noted back in August 2025. "They also offer construction of malicious commands that users will paste into the Windows Run dialog. These kits claim to guarantee antivirus and web protection bypass (some even promise that they can bypass Microsoft Defender SmartScreen), as well as payload persistence." It goes without saying that these tools further lower the barrier to entry for cybercriminals, enabling them to mount sophisticated, multi-platform attacks at scale without much effort or technical expertise. ClickFix Becomes Stealthy via Cache Smuggling The findings also follow the discovery of a new campaign that has innovated on the ClickFix attack formula by employing a sneaky technique referred to as cache smuggling to fly under the radar as opposed to explicitly downloading any malicious files on the target host. "This campaign differs from previous ClickFix variants in that the malicious script does not download any files or communicate with the internet," Expel Principal Threat Researcher Marcus Hutchins said. "This is achieved by using the browser's cache to pre-emptively store arbitrary data onto the user's machine." Expel said it was unable to determine the final payload received as part of the attack. It's also currently not known how users are redirected to the phishing page, and if it involves techniques like malvertising or search engine optimization (SEO) poisoning. In the attack documented by the cybersecurity company, the ClickFix-themed page masquerades as a Fortinet VPN Compliance Checker, using FileFix tactics to deceive users into launching the Windows File Explorer and pasting a malicious command into the address bar to trigger the execution of the payload. The invisible command is designed to run a PowerShell script via conhost.exe. What makes the script stand apart is that it does not download any additional malware or communicate with an attacker-controlled server. Instead, it executes an obfuscated payload that passes off as a JPEG image and is already cached by the browser when the user lands on the phishing page. "The file extracted from the cache is used to set up a scheduled task, which is set to run after each reboot," Hutchins told The Hacker News. "When the task runs, it connects to a command-and-control server waiting for follow-up commands." "Neither the web page nor the PowerShell script explicitly downloads any files," Hutchins explained. "By simply letting the browser cache the fake 'image,' the malware is able to get an entire ZIP file onto the local system without the PowerShell command needing to make any web requests." "The implications of this technique are concerning, as cache smuggling may offer a way to evade protections that would otherwise catch malicious files as they are downloaded and executed. An innocuous-looking 'image/jpeg' file is downloaded, only to have its contents extracted and then executed via a PowerShell command hidden in a ClickFix phishing lure." (The story was updated after publication to include additional insights from Expel.)

Check Point Research (CPR) conducted a focused analysis of Storm-2603, a threat actor associated with recent ToolShell exploitations, together with other Chinese APT groups. Storm-2603 utilizes a custom malware Command and Control (C2) framework dubbed internally by the attacker as “ak47c2”. This framework includes at least two different types of clients: HTTP-based (dubbed by us “ak47http”) and DNS-based (dubbed by us “ak47dns”). Based on VirusTotal data, Storm-2603 likely targeted some organizations in Latin America throughout the first half of 2025, in parallel to attacking organizations in APAC. Some of the actor’s TTPs align with many other ransomware groups, and involve open-source tools such as PsExec and masscan. In addition, the threat actors use a custom tool that leverages the BYOVD (Bring Your Own Vulnerable Driver) technique to tamper with endpoint protections. Storm-2603 attacks involved multiple ransomware families, sometimes bundled together. Those are commonly deployed by abusing DLL hijacking. Check Point Research (CPR) has been closely monitoring the ongoing exploitation of a group of Microsoft SharePoint Server vulnerabilities collectively referred to as “ToolShell.” These active attacks leverage four vulnerabilities—CVE-2025-49704, CVE-2025-49706, CVE-2025-53770, and CVE-2025-53771—and are attributed to multiple China affiliated threat actors. Among the threat groups identified by Microsoft, two are known APTs: Linen Typhoon (aka APT27) and Violet Typhoon (aka APT31). Another group is a newly observed, previously undocumented cluster called Storm-2603. While Microsoft linked this cluster’s activity to potential ransomware deployment, it was unable to assess the group’s objectives. As part of our ongoing investigation into ToolShell and its associated risks, we launched a targeted effort to better understand and characterize the threat posed by Storm-2603. Throughout our analysis, we uncovered several files likely tied to Storm-2603 intrusions, offering new insights that correspond to Microsoft’s description of the group. In this publication, we provide an in-depth examination of Storm-2603’s tactics, techniques, and procedures (TTPs), along with a technical breakdown of the ak47c2, a custom malware framework used in their attacks and their different ransomware payloads. Storm-2603 was first mentioned by Microsoft during investigations into a set of attacks on Microsoft SharePoint servers, known as the “ToolShell” campaign. While some activity was tied to known Chinese affiliated groups like Linen Typhoon (APT27) and Violet Typhoon (APT31), Storm-2603 appeared as a new, previously unreported actor. Microsoft linked the group to Lockbit and Warlock ransomware use. Figure 1 – Events associated with Storm-2603. Microsoft’s report provided only limited information about Storm-2603, including some of the TTPs associated with it, most of them quite generic. In addition, some of the reported indicators of compromise (IOCs) helped us uncover additional artifacts associated with previous Storm-2603 intrusions. One domain in particular, update.updatemicfosoft[.]com, linked to Storm-2603’s SharePoint exploitation, turned out to have been used in earlier campaigns dating back to March 2025. In those operations, it served as a C2 server for both DNS tunneling malware and an HTTP backdoor and was part of infrastructure used to deliver LockBit Black and Warlock/x2anylock ransomware. Our search for cases where the IOCs reported by Microsoft, revealed two incidents in which LockBit Black and WarLock ransomware variants were deployed together, in addition to multiple other tools, mostly open-source. In April 2025, a RAR archive named Evidencia.rar was uploaded to VirusTotal. The archive contains several artifacts likely extracted from compromised machines in a Storm-2603 case in a LATAM country. The artifacts in the archive provide a look at some of the open-source tools used by the actors in the intrusions which correlates with previous knowledge of the group: WinPcap – Captures and filters network traffic on Windows. PsExec – Executes commands on remote Windows systems. SharpHostInfo – Collects host and domain info on Windows environments. nxc – Exploits common vulnerabilities in network services. In addition to the open-source tools, the archive also contains the custom backdoor used by the group, as well as its unique ransomware payloads. dnsclient.exe – A custom backdoor utilized by Storm-2603 that communicates over DNS tunneling with update.updatemicfosoft[.]com, a domain associated with the group. See the next section for our analysis of the backdoor. 7z.exe & 7z.dll – Legitimate 7z executable side-loading malicious 7z.dll delivering X2anylock (aka Warlock), a ransomware used by Storm-2603. bbb.msi – An installer which uses clink_x86.exe to side-load clink_dll_x86.dll, leading to the execution of LockBit Black ransomware. Another MSI file uploaded to VirusTotal in April used a similar deployment method, starting with the MSI installer to launch multiple ransomware strains simultaneously: Figure 2 – MSI Multi-Ransomware Deployment. The MSI relies on the following files: MpCmdRun.exe & Mpclient.dll – Warlock Ransomware, deployed via DLL-hijacking. clink_x86.exe & clink_dll_x86.dll – LockBit Black ransomware, deployed via DLL-hijacking. z.exe & z.dll – x2anylock ransomware, deployed via DLL-hijacking. VMToolsEng.exe – Custom Antivirus Terminator. ServiceMouse.sys – Vulnerable driver used by VMToolsEng.exe for killing Antivirus processes. log.exe – A list of Antivirus processes to kill. msi.bat – Executes VMToolsEng.exe. 1.bat – Executes all the needed executables and the MSI. We attributed two custom backdoors to Storm-2306, both of which appear to be part of the framework named AK47 C2 based on the shared PDB path: C:\Users\Administrator\Desktop\work\tools\ak47c2\. When executed, the program immediately hides its console window, determines the host computer name (defaulting to unknown.local if that fails), and builds a DNS‑based command‑and‑control payload. It chooses a random five-character session ID, such as H4T14, and prefixes it with 1 for task requests or 2 for result uploads (e.g., 1H4T14 or 2H4T14). Each element, such as the task/result tag, a size flag (a for “all” when the entire message fits into one request), and the computer name, is XOR‑encoded with the ASCII key “VHBD@H”, converted to hexadecimal, and concatenated with dots before being prepended to the C2 domain update.micfosoft[.]com. This what the overall query looks like: DNS TXT and MG (a mail group member record type) record lookups (DnsQuery_A) are used to transmit and retrieve data. If the C2 server is unreachable, the client simply receives error 9003 (DNS_ERROR_RCODE_NAME_ERROR). Otherwise, the response text is decoded from hex, XOR‑decrypted, and parsed for the delimiter “:::”, which separates metadata from the actual command string. Commands run under cmd.exe /c 2>&1; a built‑in directive sleep n pauses execution for n seconds. For outputs larger than 0xFF bytes, the backdoor fragments data into 63‑byte sub‑segments. Each DNS query then follows: HttpClient backdoor has the pdb path C:\Users\Administrator\Desktop\work\tools\ak47c2\httpclient-cpp\x64\Release\httpclient-cpp.pdb and uses plain HTTP instead of DNS for the C2. It is built as a 64‑bit console program that also immediately hides its window on launch. On start‑up, the malware gathers the host computer name (similar to the DNS version, it defaults to unknown.local), then builds a JSON object with the fields cmd, cmd_id, fqdn, result, and type. For a task request, the object looks like this: {"cmd":"","cmd_id":"","fqdn":" ","result":"","type":"task"} After the host executes a command, the result is sent back with type:”result”. Before transmission, the entire JSON blob is XOR‑encrypted with the ASCII key “VHBD@H”, converted to hexadecimal, and placed in the body of an HTTP POST to “/” with generic headers (Content‑Type: text/plain, Accept: */*). The C2 replies with a similarly encoded JSON where the cmd field contains the next command. The implant executes it via cmd.exe /c 2>&1 and returns the output. We identified that during these attacks, several types of ransomware were deployed simultaneously. One is regular LockBit Black, and the second uses the.x2anylock extension. This extension was later used by the Warlock ransomware operator, mentioned in Microsoft’s report on the SharePoint exploitation. The Warlock ransom note is usually saved as How to decrypt my data.txt and looks like this: Figure 3 – Warlock Group ransom note. The ransom notes for all ransomware strains deployed by Storm-2603 are named How to decrypt my data.log (x2anylock) or .README.txt (LockBit Black) and have the same short content: Your decrypt ID: [redacted] Tox ID Support: 3DCE[redacted] Email Support: [redacted]@proton.me,[redacted]@proton.me,[redacted]@proton.me You can contact us in email or qtox. This ransom note’s name How to decrypt my data.log appeared in a recent LinkedIn post by Huntress, describing the case where multiple ransomware families were deployed together against the same target. While not a new tactic, this approach is rarely observed among established ransomware groups. An important part of the infection package described earlier is called Antivirus Terminator. It is a custom command line tool abusing a third-party signed legitimate driver to kill processes. From what we can see, it’s been in the wild since at least late 2024. The tool requires administrative privileges on the infected machine. The screenshot below shows how the listing is displayed in the console when the tool is run without parameters: Figure 4 – Antivirus Terminator supported arguments when run without parameters. The tool first creates a service called ServiceMouse, where the path to the service binary file is ServiceMouse.sys from the package. Next, the tool communicates with the installed service via IO control code 0x99000050, which is responsible for killing processes. The tool also has more capabilities, like deleting files and uninstalling drivers, and these use different IO control codes (0x990000D0 and 0x990001D0). Figure 6 – Antivirus Terminator kills process using third-party driver. The supplied third-party driver is a legitimate and signed component of Antiy System In-Depth Analysis Toolkit, originally named AToolsKrnl64.sys. The toolkit was developed by Antiy Labs, a Chinese security vendor, and features a graphical user interface that allows users, among others, to interact with and manipulate processes. The ability to kill processes is the most important feature which is abused by threat actors in this particular case. Figure 7 – Antiy System In-Depth Analysis Tookit GUI. The following piece of code in the driver handles the IO control code 0x99000050 mentioned above: Figure 8 – IO control code processing in the Antiy driver. The second function is the piece of code responsible for killing a process with a given PID. In this report we analyze Storm-2603, a relatively new threat actor first mentioned by Microsoft during investigations into the “ToolShell” campaign targeting SharePoint servers. While some of the exploitation activity was tied to known Chinese APT groups, Storm-2603 stood out as a previously undocumented group linked to ransomware deployment. By examining infrastructure indicators shared in public reporting, we were able to connect this actor to earlier campaigns involving LockBit Black and Warlock/X2anylock ransomware, dating back to at least March 2025. These earlier attacks used similar infrastructure and tools, including DNS tunneling and HTTP-based backdoors. Interestingly, multiple ransomware variants were deployed in the same attack. This behavior, along with the overlap in techniques, helps us better understand how Storm-2603 operates “The Turkish Rat” Evolved Adwind in a Massive Ongoing Phishing Campaign Check Point Research Publications August 11, 2017 “The Next WannaCry” Vulnerability is Here Check Point Research Publications March 12, 2026 “Handala Hack” – Unveiling Group’s Modus Operandi SUBSCRIBE TO CYBER INTELLIGENCE REPORTS We value your privacy! BFSI uses cookies on this site. We use cookies to enable faster and easier experience for you. By continuing to visit this website you agree to our use of cookies.

On July 19–20, 2025, various security companies and national CERTs published alerts about active exploitation of on-premise SharePoint servers. According to the reports, observed attacks did not require authentication, allowed attackers to gain full control over the infected servers, and were performed using an exploit chain of two vulnerabilities: CVE-2025-49704 and CVE-2025-49706, publicly named “ToolShell”. Additionally, on the same dates, Microsoft released out-of-band security patches for the vulnerabilities CVE-2025-53770 and CVE-2025-53771, aimed at addressing the security bypasses of previously issued fixes for CVE-2025-49704 and CVE-2025-49706. The release of the new, “proper” updates has caused confusion about exactly which vulnerabilities attackers are exploiting and whether they are using zero-day exploits. Kaspersky products proactively detected and blocked malicious activity linked to these attacks, which allowed us to gather statistics about the timeframe and spread of this campaign. Our statistics show that widespread exploitation started on July 18, 2025, and attackers targeted servers across the world in Egypt, Jordan, Russia, Vietnam, and Zambia. Entities across multiple sectors were affected: government, finance, manufacturing, forestry, and agriculture. While analyzing all artifacts related to these attacks, which were detected by our products and public information provided by external researchers, we found a dump of a POST request that was claimed to contain the malicious payload used in these attacks. After performing our own analysis, we were able to confirm that this dump indeed contained the malicious payload detected by our technologies, and that sending this single request to an affected SharePoint installation was enough to execute the malicious payload there. Our analysis of the exploit showed that it did rely on vulnerabilities fixed under CVE-2025-49704 and CVE-2025-49706, but by changing just one byte in the request, we were able to bypass those fixes. In this post, we provide detailed information about CVE-2025-49704, CVE-2025-49706, CVE-2025-53770, CVE-2025-53771, and one related vulnerability. Since the exploit code is already published online, is very easy to use, and poses a significant risk, we encourage all organizations to install the necessary updates. The exploit Our research started with an analysis of a POST request dump associated with this wave of attacks on SharePoint servers. We can see that this POST request targets the “/_layouts/15/ToolPane.aspx” endpoint and embeds two parameters: “MSOtlPn_Uri” and “MSOtlPn_DWP”. Looking at the code of ToolPane.aspx, we can see that this file itself does not contain much functionality and most of its code is located in the ToolPane class of the Microsoft.SharePoint.WebPartPages namespace in Microsoft.SharePoint.dll. Looking at this class reveals the code that works with the two parameters present in the exploit. However, accessing this endpoint under normal conditions is not possible without bypassing authentication on the attacked SharePoint server. This is where the first Microsoft SharePoint Server Spoofing Vulnerability CVE-2025-49706 comes into play. CVE-2025-49706 This vulnerability is present in the method PostAuthenticateRequestHandler, in Microsoft.SharePoint.dll. SharePoint requires Internet Information Services (IIS) to be configured in integrated mode. In this mode, the IIS and ASP.NET authentication stages are unified. As a result, the outcome of IIS authentication is not determined until the PostAuthenticateRequest stage, at which point both the ASP.NET and IIS authentication methods have been completed. Therefore, the PostAuthenticateRequestHandler method utilizes a series of flags to track potential authentication violations. A logic bug in this method enables an authentication bypass if the “Referrer” header of the HTTP request is equal to “/_layouts/SignOut.aspx”, “/_layouts/14/SignOut.aspx”, or “/_layouts/15/SignOut.aspx” using case insensitive comparison. The code displayed in the image above handles the sign-out request and is also triggered when the sign-out page is specified as the referrer. When flag6 is set to false and flag7 is set to true, both conditional branches that could potentially throw an “Unauthorized Access” exception are bypassed. On July 8, 2025, Microsoft released an update that addressed this vulnerability by introducing additional checks to detect the usage of the “ToolPane.aspx” endpoint with the sign-out page specified as the referrer. The added check uses case insensitive comparison to verify if the requested path ends with “ToolPane.aspx”. Is it possible to bypass this check, say, by using a different endpoint? Our testing has shown that this check can be easily bypassed. CVE-2025-53771 We were able to successfully bypass the patch for vulnerability CVE-2025-49706 by adding just one byte to the exploit POST request. All that was required to bypass this patch was to add a “/” (slash) to the end of the requested “ToolPane.aspx” path. On July 20, 2025, Microsoft released an update that fixed this bypass as CVE-2025-53771. This fix replaces the “ToolPane.aspx” check to instead check whether the requested path is in the list of paths allowed for use with the sign-out page specified as the referrer. This allowlist includes the following paths: “/_layouts/15/SignOut.aspx”, “/_layouts/15/1033/initstrings.js”, “/_layouts/15/init.js”, “/_layouts/15/theming.js”, “/ScriptResource.axd”, “/_layouts/15/blank.js”, “/ScriptResource.axd”, “/WebResource.axd”, “/_layouts/15/1033/styles/corev15.css”, “/_layouts/15/1033/styles/error.css”, “/_layouts/15/images/favicon.ico”, “/_layouts/15/1033/strings.js”, “/_layouts/15/core.js”, and it can contain additional paths added by the administrator. While testing the CVE-2025-49706 bypass with the July 8, 2025 updates installed on our SharePoint debugging stand, we noticed some strange behavior. Not only did the bypass of CVE-2025-49706 work, but the entire exploit chain did! But wait! Didn’t the attackers use an additional Microsoft SharePoint Remote Code Execution Vulnerability CVE-2025-49704, which was supposed to be fixed in the same update? To understand why the entire exploit chain worked in our case, let’s take a look at the vulnerability CVE-2025-49704 and how it was fixed. CVE-2025-49704 CVE-2025-49704 is an untrusted data deserialization vulnerability that exists due to improper validation of XML content. Looking at the exploit POST request, we can see that it contains two URL encoded parameters: “MSOtlPn_Uri” and “MSOtlPn_DWP”. We can see how they are handled by examining the code of the method GetPartPreviewAndPropertiesFromMarkup in Microsoft.SharePoint.dll. A quick analysis reveals that “MSOtlPn_Uri” is a page URL that might be pointing to an any file in the CONTROLTEMPLATES folder and the parameter “MSOtlPn_DWP” contains something known as WebPart markup. This markup contains special directives that can be used to execute safe controls on a server and has a format very similar to XML. While this “XML” included in the “MSOtlPn_DWP” parameter does not itself contain a vulnerability, it allows attackers to instantiate the ExcelDataSet control from Microsoft.PerformancePoint.Scorecards.Client.dll with CompressedDataTable property set to malicious payload and trigger its processing using DataTable property getter. Looking at the code of the ExcelDataSet’s DataTable property getter in Microsoft.PerformancePoint.Scorecards.Client.dll, we find the method GetObjectFromCompressedBase64String, responsible for deserialization of CompressedDataTable property contents. The data provided as Base64 string is decoded, unzipped, and passed to the BinarySerialization.Deserialize method from Microsoft.SharePoint.dll. Attackers use this method to provide a malicious DataSet whose deserialized content is shown in the image above. It contains an XML with an element of dangerous type "System.Collections.Generic.List1[[System.Data.Services.Internal.ExpandedWrapper2[...], System.Data.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]", which allows attackers to execute arbitrary methods with the help of the well-known ExpandedWrapper technique aimed at exploitation of unsafe XML deserialization in applications based on the .NET framework. In fact, this shouldn’t be possible, since BinarySerialization.Deserialize in Microsoft.SharePoint.dll uses a special XmlValidator designed to protect against this technique by checking the types of all elements present in the provided XML and ensuring that they are on the list of allowed types. However, the exploit bypasses this check by placing the ExpandedWrapper object into the list. Now, to find out why the exploit worked on our SharePoint debugging stand with the July 8, 2025 updates installed, let’s take a look at how this vulnerability was fixed. In this patch, Microsoft did not really fix the vulnerability but only mitigated it by adding the new AddExcelDataSetToSafeControls class to the Microsoft.SharePoint.Upgrade namespace. This class contains new code that modifies the web.config file and marks the Microsoft.PerformancePoint.Scorecards.ExcelDataSet control as unsafe. Because SharePoint does not execute this code on its own after installing updates, the only way to achieve the security effect was to manually run a configuration upgrade using the SharePoint Products Configuration Wizard tool. Notably, the security guidance for CVE-2025-49704 does not mention the need for this step, which means at least some SharePoint administrators may skip it. Meanwhile, anyone who installed this update but did not manually perform a configuration upgrade remained vulnerable. CVE-2025-53770 On July 20, 2025, Microsoft released an update with a proper fix for the CVE-2025-49704 vulnerability. This patch introduces an updated XmlValidator that now properly validates element types in XML, preventing exploitation of this vulnerability without requiring a configuration upgrade and, more importantly, addressing the root cause and preventing exploitation of the same vulnerability through controls other than Microsoft.PerformancePoint.Scorecards.ExcelDataSet. CVE-2020-1147 Readers familiar with previous SharePoint exploits might feel that the vulnerability CVE-2025-49704/CVE-2025-53770 and the exploit used by the attackers looks very familiar and very similar to the older .NET Framework, SharePoint Server, and Visual Studio Remote Code Execution Vulnerability CVE-2020-1147. In fact, if we compare the exploit for CVE-2020-1147 and an exploit for CVE-2025-49704/CVE-2025-53770, we can see that they are almost identical. The only difference is that in the exploit for CVE-2025-49704/CVE-2025-53770, the dangerous ExpandedWrapper object is placed in the list. This makes CVE-2025-53770 an updated fix for CVE-2020-1147. Conclusions Despite the fact that patches for the ToolShell vulnerabilities are now available for deployment, we assess that this chain of exploits will continue being used by attackers for a long time. We have been observing the same situation with other notorious vulnerabilities, such as ProxyLogon, PrintNightmare, or EternalBlue. While they have been known for years, many threat actors still continue leveraging them in their attacks to compromise unpatched systems. We expect the ToolShell vulnerabilities to follow the same fate, as they can be exploited with extremely low effort and allow full control over the vulnerable server. To stay better protected against threats like ToolShell, we as a community should learn lessons from previous events in the industry related to critical vulnerabilities. Specifically, the speed of applying security patches nowadays is the most important factor when it comes to fighting such vulnerabilities. Since public exploits for these dangerous vulnerabilities appear very soon after vulnerability announcements, it is paramount to install patches as soon as possible, as a gap of even a few hours can make a critical difference. At the same time, it is important to protect enterprise networks against zero-day exploits, which can be leveraged when there is no available public patch for vulnerabilities. In this regard, it is critical to equip machines with reliable cybersecurity solutions that have proven effective in combatting ToolShell attacks before they were publicly disclosed. Kaspersky Next with its Behaviour detection component proactively protects against exploitation of these vulnerabilities. Additionally, it is able to detect exploitation and the subsequent malicious activity. Kaspersky products detect the exploits and malware used in these attacks with the following verdicts: UDS:DangerousObject.Multi.Generic PDM:Exploit.Win32.Generic PDM:Trojan.Win32.Generic HEUR:Trojan.MSIL.Agent.gen ASP.Agent.* PowerShell.Agent.*

On July 19–20, 2025, various security companies and national CERTs published alerts about active exploitation of on-premise SharePoint servers. According to the reports, observed attacks did not require authentication, allowed attackers to gain full control over the infected servers, and were performed using an exploit chain of two vulnerabilities: CVE-2025-49704 and CVE-2025-49706, publicly named “ToolShell”. Additionally, on the same dates, Microsoft released out-of-band security patches for the vulnerabilities CVE-2025-53770 and CVE-2025-53771, aimed at addressing the security bypasses of previously issued fixes for CVE-2025-49704 and CVE-2025-49706. The release of the new, “proper” updates has caused confusion about exactly which vulnerabilities attackers are exploiting and whether they are using zero-day exploits. Kaspersky products proactively detected and blocked malicious activity linked to these attacks, which allowed us to gather statistics about the timeframe and spread of this campaign. Our statistics show that widespread exploitation started on July 18, 2025, and attackers targeted servers across the world in Egypt, Jordan, Russia, Vietnam, and Zambia. Entities across multiple sectors were affected: government, finance, manufacturing, forestry, and agriculture. While analyzing all artifacts related to these attacks, which were detected by our products and public information provided by external researchers, we found a dump of a POST request that was claimed to contain the malicious payload used in these attacks. After performing our own analysis, we were able to confirm that this dump indeed contained the malicious payload detected by our technologies, and that sending this single request to an affected SharePoint installation was enough to execute the malicious payload there. Our analysis of the exploit showed that it did rely on vulnerabilities fixed under CVE-2025-49704 and CVE-2025-49706, but by changing just one byte in the request, we were able to bypass those fixes. In this post, we provide detailed information about CVE-2025-49704, CVE-2025-49706, CVE-2025-53770, CVE-2025-53771, and one related vulnerability. Since the exploit code is already published online, is very easy to use, and poses a significant risk, we encourage all organizations to install the necessary updates. The exploit Our research started with an analysis of a POST request dump associated with this wave of attacks on SharePoint servers. We can see that this POST request targets the “/_layouts/15/ToolPane.aspx” endpoint and embeds two parameters: “MSOtlPn_Uri” and “MSOtlPn_DWP”. Looking at the code of ToolPane.aspx, we can see that this file itself does not contain much functionality and most of its code is located in the ToolPane class of the Microsoft.SharePoint.WebPartPages namespace in Microsoft.SharePoint.dll. Looking at this class reveals the code that works with the two parameters present in the exploit. However, accessing this endpoint under normal conditions is not possible without bypassing authentication on the attacked SharePoint server. This is where the first Microsoft SharePoint Server Spoofing Vulnerability CVE-2025-49706 comes into play. CVE-2025-49706 This vulnerability is present in the method PostAuthenticateRequestHandler, in Microsoft.SharePoint.dll. SharePoint requires Internet Information Services (IIS) to be configured in integrated mode. In this mode, the IIS and ASP.NET authentication stages are unified. As a result, the outcome of IIS authentication is not determined until the PostAuthenticateRequest stage, at which point both the ASP.NET and IIS authentication methods have been completed. Therefore, the PostAuthenticateRequestHandler method utilizes a series of flags to track potential authentication violations. A logic bug in this method enables an authentication bypass if the “Referrer” header of the HTTP request is equal to “/_layouts/SignOut.aspx”, “/_layouts/14/SignOut.aspx”, or “/_layouts/15/SignOut.aspx” using case insensitive comparison. The code displayed in the image above handles the sign-out request and is also triggered when the sign-out page is specified as the referrer. When flag6 is set to false and flag7 is set to true, both conditional branches that could potentially throw an “Unauthorized Access” exception are bypassed. On July 8, 2025, Microsoft released an update that addressed this vulnerability by introducing additional checks to detect the usage of the “ToolPane.aspx” endpoint with the sign-out page specified as the referrer. The added check uses case insensitive comparison to verify if the requested path ends with “ToolPane.aspx”. Is it possible to bypass this check, say, by using a different endpoint? Our testing has shown that this check can be easily bypassed. CVE-2025-53771 We were able to successfully bypass the patch for vulnerability CVE-2025-49706 by adding just one byte to the exploit POST request. All that was required to bypass this patch was to add a “/” (slash) to the end of the requested “ToolPane.aspx” path. On July 20, 2025, Microsoft released an update that fixed this bypass as CVE-2025-53771. This fix replaces the “ToolPane.aspx” check to instead check whether the requested path is in the list of paths allowed for use with the sign-out page specified as the referrer. This allowlist includes the following paths: “/_layouts/15/SignOut.aspx”, “/_layouts/15/1033/initstrings.js”, “/_layouts/15/init.js”, “/_layouts/15/theming.js”, “/ScriptResource.axd”, “/_layouts/15/blank.js”, “/ScriptResource.axd”, “/WebResource.axd”, “/_layouts/15/1033/styles/corev15.css”, “/_layouts/15/1033/styles/error.css”, “/_layouts/15/images/favicon.ico”, “/_layouts/15/1033/strings.js”, “/_layouts/15/core.js”, and it can contain additional paths added by the administrator. While testing the CVE-2025-49706 bypass with the July 8, 2025 updates installed on our SharePoint debugging stand, we noticed some strange behavior. Not only did the bypass of CVE-2025-49706 work, but the entire exploit chain did! But wait! Didn’t the attackers use an additional Microsoft SharePoint Remote Code Execution Vulnerability CVE-2025-49704, which was supposed to be fixed in the same update? To understand why the entire exploit chain worked in our case, let’s take a look at the vulnerability CVE-2025-49704 and how it was fixed. CVE-2025-49704 CVE-2025-49704 is an untrusted data deserialization vulnerability that exists due to improper validation of XML content. Looking at the exploit POST request, we can see that it contains two URL encoded parameters: “MSOtlPn_Uri” and “MSOtlPn_DWP”. We can see how they are handled by examining the code of the method GetPartPreviewAndPropertiesFromMarkup in Microsoft.SharePoint.dll. A quick analysis reveals that “MSOtlPn_Uri” is a page URL that might be pointing to an any file in the CONTROLTEMPLATES folder and the parameter “MSOtlPn_DWP” contains something known as WebPart markup. This markup contains special directives that can be used to execute safe controls on a server and has a format very similar to XML. While this “XML” included in the “MSOtlPn_DWP” parameter does not itself contain a vulnerability, it allows attackers to instantiate the ExcelDataSet control from Microsoft.PerformancePoint.Scorecards.Client.dll with CompressedDataTable property set to malicious payload and trigger its processing using DataTable property getter. Looking at the code of the ExcelDataSet’s DataTable property getter in Microsoft.PerformancePoint.Scorecards.Client.dll, we find the method GetObjectFromCompressedBase64String, responsible for deserialization of CompressedDataTable property contents. The data provided as Base64 string is decoded, unzipped, and passed to the BinarySerialization.Deserialize method from Microsoft.SharePoint.dll. Attackers use this method to provide a malicious DataSet whose deserialized content is shown in the image above. It contains an XML with an element of dangerous type "System.Collections.Generic.List1[[System.Data.Services.Internal.ExpandedWrapper2[...], System.Data.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]", which allows attackers to execute arbitrary methods with the help of the well-known ExpandedWrapper technique aimed at exploitation of unsafe XML deserialization in applications based on the .NET framework. In fact, this shouldn’t be possible, since BinarySerialization.Deserialize in Microsoft.SharePoint.dll uses a special XmlValidator designed to protect against this technique by checking the types of all elements present in the provided XML and ensuring that they are on the list of allowed types. However, the exploit bypasses this check by placing the ExpandedWrapper object into the list. Now, to find out why the exploit worked on our SharePoint debugging stand with the July 8, 2025 updates installed, let’s take a look at how this vulnerability was fixed. In this patch, Microsoft did not really fix the vulnerability but only mitigated it by adding the new AddExcelDataSetToSafeControls class to the Microsoft.SharePoint.Upgrade namespace. This class contains new code that modifies the web.config file and marks the Microsoft.PerformancePoint.Scorecards.ExcelDataSet control as unsafe. Because SharePoint does not execute this code on its own after installing updates, the only way to achieve the security effect was to manually run a configuration upgrade using the SharePoint Products Configuration Wizard tool. Notably, the security guidance for CVE-2025-49704 does not mention the need for this step, which means at least some SharePoint administrators may skip it. Meanwhile, anyone who installed this update but did not manually perform a configuration upgrade remained vulnerable. CVE-2025-53770 On July 20, 2025, Microsoft released an update with a proper fix for the CVE-2025-49704 vulnerability. This patch introduces an updated XmlValidator that now properly validates element types in XML, preventing exploitation of this vulnerability without requiring a configuration upgrade and, more importantly, addressing the root cause and preventing exploitation of the same vulnerability through controls other than Microsoft.PerformancePoint.Scorecards.ExcelDataSet. CVE-2020-1147 Readers familiar with previous SharePoint exploits might feel that the vulnerability CVE-2025-49704/CVE-2025-53770 and the exploit used by the attackers looks very familiar and very similar to the older .NET Framework, SharePoint Server, and Visual Studio Remote Code Execution Vulnerability CVE-2020-1147. In fact, if we compare the exploit for CVE-2020-1147 and an exploit for CVE-2025-49704/CVE-2025-53770, we can see that they are almost identical. The only difference is that in the exploit for CVE-2025-49704/CVE-2025-53770, the dangerous ExpandedWrapper object is placed in the list. This makes CVE-2025-53770 an updated fix for CVE-2020-1147. Conclusions Despite the fact that patches for the ToolShell vulnerabilities are now available for deployment, we assess that this chain of exploits will continue being used by attackers for a long time. We have been observing the same situation with other notorious vulnerabilities, such as ProxyLogon, PrintNightmare, or EternalBlue. While they have been known for years, many threat actors still continue leveraging them in their attacks to compromise unpatched systems. We expect the ToolShell vulnerabilities to follow the same fate, as they can be exploited with extremely low effort and allow full control over the vulnerable server. To stay better protected against threats like ToolShell, we as a community should learn lessons from previous events in the industry related to critical vulnerabilities. Specifically, the speed of applying security patches nowadays is the most important factor when it comes to fighting such vulnerabilities. Since public exploits for these dangerous vulnerabilities appear very soon after vulnerability announcements, it is paramount to install patches as soon as possible, as a gap of even a few hours can make a critical difference. At the same time, it is important to protect enterprise networks against zero-day exploits, which can be leveraged when there is no available public patch for vulnerabilities. In this regard, it is critical to equip machines with reliable cybersecurity solutions that have proven effective in combatting ToolShell attacks before they were publicly disclosed. Kaspersky Next with its Behaviour detection component proactively protects against exploitation of these vulnerabilities. Additionally, it is able to detect exploitation and the subsequent malicious activity. Kaspersky products detect the exploits and malware used in these attacks with the following verdicts: UDS:DangerousObject.Multi.Generic PDM:Exploit.Win32.Generic PDM:Trojan.Win32.Generic HEUR:Trojan.MSIL.Agent.gen ASP.Agent.* PowerShell.Agent.*

Check Point Research (CPR) conducted a focused analysis of Storm-2603, a threat actor associated with recent ToolShell exploitations, together with other Chinese APT groups. Storm-2603 utilizes a custom malware Command and Control (C2) framework dubbed internally by the attacker as “ak47c2”. This framework includes at least two different types of clients: HTTP-based (dubbed by us “ak47http”) and DNS-based (dubbed by us “ak47dns”). Based on VirusTotal data, Storm-2603 likely targeted some organizations in Latin America throughout the first half of 2025, in parallel to attacking organizations in APAC. Some of the actor’s TTPs align with many other ransomware groups, and involve open-source tools such as PsExec and masscan. In addition, the threat actors use a custom tool that leverages the BYOVD (Bring Your Own Vulnerable Driver) technique to tamper with endpoint protections. Storm-2603 attacks involved multiple ransomware families, sometimes bundled together. Those are commonly deployed by abusing DLL hijacking. Check Point Research (CPR) has been closely monitoring the ongoing exploitation of a group of Microsoft SharePoint Server vulnerabilities collectively referred to as “ToolShell.” These active attacks leverage four vulnerabilities—CVE-2025-49704, CVE-2025-49706, CVE-2025-53770, and CVE-2025-53771—and are attributed to multiple China affiliated threat actors. Among the threat groups identified by Microsoft, two are known APTs: Linen Typhoon (aka APT27) and Violet Typhoon (aka APT31). Another group is a newly observed, previously undocumented cluster called Storm-2603. While Microsoft linked this cluster’s activity to potential ransomware deployment, it was unable to assess the group’s objectives. As part of our ongoing investigation into ToolShell and its associated risks, we launched a targeted effort to better understand and characterize the threat posed by Storm-2603. Throughout our analysis, we uncovered several files likely tied to Storm-2603 intrusions, offering new insights that correspond to Microsoft’s description of the group. In this publication, we provide an in-depth examination of Storm-2603’s tactics, techniques, and procedures (TTPs), along with a technical breakdown of the ak47c2, a custom malware framework used in their attacks and their different ransomware payloads. Storm-2603 was first mentioned by Microsoft during investigations into a set of attacks on Microsoft SharePoint servers, known as the “ToolShell” campaign. While some activity was tied to known Chinese affiliated groups like Linen Typhoon (APT27) and Violet Typhoon (APT31), Storm-2603 appeared as a new, previously unreported actor. Microsoft linked the group to Lockbit and Warlock ransomware use. Figure 1 – Events associated with Storm-2603. Microsoft’s report provided only limited information about Storm-2603, including some of the TTPs associated with it, most of them quite generic. In addition, some of the reported indicators of compromise (IOCs) helped us uncover additional artifacts associated with previous Storm-2603 intrusions. One domain in particular, update.updatemicfosoft[.]com, linked to Storm-2603’s SharePoint exploitation, turned out to have been used in earlier campaigns dating back to March 2025. In those operations, it served as a C2 server for both DNS tunneling malware and an HTTP backdoor and was part of infrastructure used to deliver LockBit Black and Warlock/x2anylock ransomware. Our search for cases where the IOCs reported by Microsoft, revealed two incidents in which LockBit Black and WarLock ransomware variants were deployed together, in addition to multiple other tools, mostly open-source. In April 2025, a RAR archive named Evidencia.rar was uploaded to VirusTotal. The archive contains several artifacts likely extracted from compromised machines in a Storm-2603 case in a LATAM country. The artifacts in the archive provide a look at some of the open-source tools used by the actors in the intrusions which correlates with previous knowledge of the group: WinPcap – Captures and filters network traffic on Windows. PsExec – Executes commands on remote Windows systems. SharpHostInfo – Collects host and domain info on Windows environments. nxc – Exploits common vulnerabilities in network services. In addition to the open-source tools, the archive also contains the custom backdoor used by the group, as well as its unique ransomware payloads. dnsclient.exe – A custom backdoor utilized by Storm-2603 that communicates over DNS tunneling with update.updatemicfosoft[.]com, a domain associated with the group. See the next section for our analysis of the backdoor. 7z.exe & 7z.dll – Legitimate 7z executable side-loading malicious 7z.dll delivering X2anylock (aka Warlock), a ransomware used by Storm-2603. bbb.msi – An installer which uses clink_x86.exe to side-load clink_dll_x86.dll, leading to the execution of LockBit Black ransomware. Another MSI file uploaded to VirusTotal in April used a similar deployment method, starting with the MSI installer to launch multiple ransomware strains simultaneously: Figure 2 – MSI Multi-Ransomware Deployment. The MSI relies on the following files: MpCmdRun.exe & Mpclient.dll – Warlock Ransomware, deployed via DLL-hijacking. clink_x86.exe & clink_dll_x86.dll – LockBit Black ransomware, deployed via DLL-hijacking. z.exe & z.dll – x2anylock ransomware, deployed via DLL-hijacking. VMToolsEng.exe – Custom Antivirus Terminator. ServiceMouse.sys – Vulnerable driver used by VMToolsEng.exe for killing Antivirus processes. log.exe – A list of Antivirus processes to kill. msi.bat – Executes VMToolsEng.exe. 1.bat – Executes all the needed executables and the MSI. We attributed two custom backdoors to Storm-2306, both of which appear to be part of the framework named AK47 C2 based on the shared PDB path: C:\Users\Administrator\Desktop\work\tools\ak47c2\. When executed, the program immediately hides its console window, determines the host computer name (defaulting to unknown.local if that fails), and builds a DNS‑based command‑and‑control payload. It chooses a random five-character session ID, such as H4T14, and prefixes it with 1 for task requests or 2 for result uploads (e.g., 1H4T14 or 2H4T14). Each element, such as the task/result tag, a size flag (a for “all” when the entire message fits into one request), and the computer name, is XOR‑encoded with the ASCII key “VHBD@H”, converted to hexadecimal, and concatenated with dots before being prepended to the C2 domain update.micfosoft[.]com. This what the overall query looks like: DNS TXT and MG (a mail group member record type) record lookups (DnsQuery_A) are used to transmit and retrieve data. If the C2 server is unreachable, the client simply receives error 9003 (DNS_ERROR_RCODE_NAME_ERROR). Otherwise, the response text is decoded from hex, XOR‑decrypted, and parsed for the delimiter “:::”, which separates metadata from the actual command string. Commands run under cmd.exe /c 2>&1; a built‑in directive sleep n pauses execution for n seconds. For outputs larger than 0xFF bytes, the backdoor fragments data into 63‑byte sub‑segments. Each DNS query then follows: HttpClient backdoor has the pdb path C:\Users\Administrator\Desktop\work\tools\ak47c2\httpclient-cpp\x64\Release\httpclient-cpp.pdb and uses plain HTTP instead of DNS for the C2. It is built as a 64‑bit console program that also immediately hides its window on launch. On start‑up, the malware gathers the host computer name (similar to the DNS version, it defaults to unknown.local), then builds a JSON object with the fields cmd, cmd_id, fqdn, result, and type. For a task request, the object looks like this: {"cmd":"","cmd_id":"","fqdn":" ","result":"","type":"task"} After the host executes a command, the result is sent back with type:”result”. Before transmission, the entire JSON blob is XOR‑encrypted with the ASCII key “VHBD@H”, converted to hexadecimal, and placed in the body of an HTTP POST to “/” with generic headers (Content‑Type: text/plain, Accept: */*). The C2 replies with a similarly encoded JSON where the cmd field contains the next command. The implant executes it via cmd.exe /c 2>&1 and returns the output. We identified that during these attacks, several types of ransomware were deployed simultaneously. One is regular LockBit Black, and the second uses the.x2anylock extension. This extension was later used by the Warlock ransomware operator, mentioned in Microsoft’s report on the SharePoint exploitation. The Warlock ransom note is usually saved as How to decrypt my data.txt and looks like this: Figure 3 – Warlock Group ransom note. The ransom notes for all ransomware strains deployed by Storm-2603 are named How to decrypt my data.log (x2anylock) or .README.txt (LockBit Black) and have the same short content: Your decrypt ID: [redacted] Tox ID Support: 3DCE[redacted] Email Support: [redacted]@proton.me,[redacted]@proton.me,[redacted]@proton.me You can contact us in email or qtox. This ransom note’s name How to decrypt my data.log appeared in a recent LinkedIn post by Huntress, describing the case where multiple ransomware families were deployed together against the same target. While not a new tactic, this approach is rarely observed among established ransomware groups. An important part of the infection package described earlier is called Antivirus Terminator. It is a custom command line tool abusing a third-party signed legitimate driver to kill processes. From what we can see, it’s been in the wild since at least late 2024. The tool requires administrative privileges on the infected machine. The screenshot below shows how the listing is displayed in the console when the tool is run without parameters: Figure 4 – Antivirus Terminator supported arguments when run without parameters. The tool first creates a service called ServiceMouse, where the path to the service binary file is ServiceMouse.sys from the package. Next, the tool communicates with the installed service via IO control code 0x99000050, which is responsible for killing processes. The tool also has more capabilities, like deleting files and uninstalling drivers, and these use different IO control codes (0x990000D0 and 0x990001D0). Figure 6 – Antivirus Terminator kills process using third-party driver. The supplied third-party driver is a legitimate and signed component of Antiy System In-Depth Analysis Toolkit, originally named AToolsKrnl64.sys. The toolkit was developed by Antiy Labs, a Chinese security vendor, and features a graphical user interface that allows users, among others, to interact with and manipulate processes. The ability to kill processes is the most important feature which is abused by threat actors in this particular case. Figure 7 – Antiy System In-Depth Analysis Tookit GUI. The following piece of code in the driver handles the IO control code 0x99000050 mentioned above: Figure 8 – IO control code processing in the Antiy driver. The second function is the piece of code responsible for killing a process with a given PID. In this report we analyze Storm-2603, a relatively new threat actor first mentioned by Microsoft during investigations into the “ToolShell” campaign targeting SharePoint servers. While some of the exploitation activity was tied to known Chinese APT groups, Storm-2603 stood out as a previously undocumented group linked to ransomware deployment. By examining infrastructure indicators shared in public reporting, we were able to connect this actor to earlier campaigns involving LockBit Black and Warlock/X2anylock ransomware, dating back to at least March 2025. These earlier attacks used similar infrastructure and tools, including DNS tunneling and HTTP-based backdoors. Interestingly, multiple ransomware variants were deployed in the same attack. This behavior, along with the overlap in techniques, helps us better understand how Storm-2603 operates “The Turkish Rat” Evolved Adwind in a Massive Ongoing Phishing Campaign Check Point Research Publications August 11, 2017 “The Next WannaCry” Vulnerability is Here Check Point Research Publications March 12, 2026 “Handala Hack” – Unveiling Group’s Modus Operandi SUBSCRIBE TO CYBER INTELLIGENCE REPORTS We value your privacy! BFSI uses cookies on this site. We use cookies to enable faster and easier experience for you. By continuing to visit this website you agree to our use of cookies.