SonicWall: rilevato sfruttamento in rete delle CVE-2026-83548 e CVE-2026-83549

Malware linked to break-ins at F5 BIG-IP Access Policy Manager appliances hides a PHP web shell in memory instead of in a file on disk, Sophos said in an analysis published on September 7. When Apache loads any of the three appliances' own PHP scripts, the malware adds the web shell to the copy held in memory, so a check of the file on disk can come back clean. Those three scripts are the same ones F5 pointed customers to in March, when it said changes to them alone do not show a break-in. A web shell is usually a small script an attacker drops into a web server's folders to run commands through ordinary web requests. Because it sits on disk, defenders look for it by scanning files and comparing them against known-good copies. That approach does not work here. As the researchers put it, the web shell "does not need to exist in its final form on disk." The three scripts are apm_css.php3, full_wt.php3 and webtop_popup_css.php3, part of the BIG-IP APM webtop. F5 named all three in March in a published list of indicators of compromise for the malware it tracks as c05d5254, and said at the time that their presence alone does not point to a security problem. F5 also said it had seen cases where a web shell was written to disk, but that the web shells "have been observed to work in memory only," which means the files it listed might not be modified. The Sophos analysis explains how both statements can be true at once. Sophos examined a single sample. Its analysis names no victim and does not say how the sample was obtained. F5 has linked the c05d5254 activity to appliances affected by CVE-2025-53521, Sophos said. F5 first published that flaw on October 15, 2025, as a denial-of-service problem. On March 27, 2026, F5 said new information had led it to reclassify the flaw as remote code execution, and that it had been exploited. An attacker needs no login to use it, and F5 rates it 9.8 on CVSS 3.1 and 9.3 on CVSS 4.0. CISA added it to its Known Exploited Vulnerabilities catalog the same day, giving U.S. federal civilian agencies until March 30 to act. The flaw applies where a BIG-IP APM access policy is set on a virtual server. The UK's National Cyber Security Center calls BIG-IP APM a common component, especially in large organizations. F5's advisory lists the affected and fixed releases. The patch that fixes this is nearly a year old. Ireland's National Cyber Security Center said in a March 31 advisory that the patch released in October is still valid and will protect against exploitation. The web shell is the last step in a longer chain, and the earlier steps do touch the disk. Sophos said a separate installer, found in a sample named umount, infects the Apache web server program at /usr/sbin/httpd by adding malicious code to the front of the real file. The size of that added code matches the payload carried inside the installer, which Sophos said strongly suggests the installer puts it there. ESET, which analyzed related samples in April and named the malware PoisonedRefresh, said the installer is meant to be run as root and turns off SELinux. It also infects umount, httpd and rc.local inside BIG-IP install images, which ESET said was presumably done to spread the malware to other systems through the installation media. Because the malware sits inside the Apache program, it runs before Apache's own code starts. Sophos said it hooks an Apache Portable Runtime function, apr_dso_load, and does nothing until Apache loads the PHP module, libphp. Once PHP is loaded, the malware reads /proc/self/maps to find the module in memory, briefly makes those memory pages writable, rewrites the calls the module uses to open, size, and map files, then puts the original permissions back. From that point, it controls what PHP sees when it opens one of the three scripts. When the file is mapped into memory, the malware places the web shell in front of the original content. The web shell reads the raw body of a request, checks it for a short marker, decrypts the rest, and runs it. It replies with HTTP status 201 and a CSS content type, so the exchange looks like a request for a stylesheet. The malware also opens a local socket at /run/bigtlog.pipe. After checking for a fixed token, it connects that socket to /bin/bash, giving an interactive shell without opening a network port. Sophos said it could not find any code in the sample for connecting to that socket, and no other use of the token, so the two ways in look like separate features. It has no evidence either way on whether the attacker reaches the socket through the web shell. What Defenders Can Check Sophos said its behavioral signals are leads to investigate, not proof on their own, and should be read alongside file, process, and memory evidence. The list below combines them with the indicators F5 published in March. File: /run/bigtlog.pipe or /run/bigstart.ltm present Binary: hash, size or timestamp mismatch on /usr/bin/umount or /usr/sbin/httpd against a known good copy. F5 notes that sizes and timestamps differ between releases and engineering hotfixes Tool: sys-eicheck failing because one of those two files has changed Log: an entry in /var/log/restjavad-audit showing a local user reaching the iControl REST API from localhost Log: an entry in /var/log/auditd showing SELinux being switched off by the same route Log: an entry in /var/log/audit showing a bash command run through iControl REST. F5 says these lines show base64 data written into a file and /run/bigstart.ltm being run Traffic: HTTP 201 responses carrying a CSS content type from the appliance Host behavior: an Apache worker reading /proc/self/maps, changing memory permissions around libphp, binding a socket under /run, or starting /bin/bash SHA-256: 26bd5b0722d1dbab5db749a063c49bc8638653ac2addfead7a9cb3d6d57bccc9 File, weak on its own: changes to the three .php3 scripts. F5 says their presence alone does not show a problem, and the Sophos analysis explains why: the file does not have to change at all F5's list also includes items the Sophos analysis does not cover, among them /run/bigstart.ltm and the changes affecting sys-eicheck. Neither account describes the whole intrusion. If You Have Already Patched Patching does not settle whether an appliance was compromised before the patch went on. Ireland's NCSC said no timeline for exploitation is available, and that it expects some exploitation was or could have been happening before the flaw and its fix were first published in October 2025. The UK's NCSC advises investigating for compromise "regardless of when the system was updated." Run F5's built-in sys-eicheck integrity check. F5's own indicators say the changes to /usr/bin/umount and /usr/sbin/httpd make this tool fail, so a failure is itself the signal. Collect a qkview report, send it to F5 and raise a case. Ireland's NCSC said F5 can check that report for signs of compromise, and that raising an associated case brings a quicker and fuller response. Compare the contents of modules in memory against the copies on disk, which Sophos recommends adding to incident response playbooks for critical web servers. Where a full investigation is not possible, the UK NCSC advises isolating the appliance and rebuilding it as new, and says this may cause an outage. Three things are still unknown. F5 has not said when exploitation began. None of the published advisories or analyses say whether upgrading an appliance to a fixed release removes malware already installed on it, and both Sophos and ESET describe a component designed to survive upgrade images. And no one has named an attacker: Sophos said it does not have enough evidence to name a group, and ESET said in April that it had not settled the question either.

Some attacks take real skill. Others just need someone to leave a door open. This week has both. Exposed passwords, old bugs still getting exploited, and trusted software doing things it shouldn't. There's a strange mix of clever tricks and careless mistakes. Hackers are borrowing trust from familiar apps, websites, and AI tools. Some are using AI to speed things up. Others are leaving their own attack files exposed. Not exactly careful work. Different stories, familiar weak spots. Here's what showed up this week. The threats change every week. Subscribe, and we’ll alert you when each new ThreatsDay Bulletin is out. PHP2Shell attacks persist WordPress security company Wordefence said it's not aware of any WordPress site compromised through PHP2Shell (CVE-2026-109618 and CVE-2026-109619) as of October 28, 2026. "We continue to see PHP2Shell-related requests across the more than 5 million sites we protect," it said. "Those requests show ongoing scanning and exploitation attempts; they do not show whether an attempt succeeded. Our site-cleaning and incident response teams have not handled a WordPress compromise attributed to these vulnerabilities." 40,573 secrets exposed Hudson Rock's investigation into the FortiBleed credential harvesting campaign has uncovered 975 newly identified domains and 40,573 exposed secrets, including 37,076 local-user records and 1,576 Active Directory LDAP bind records. The data comes from newly obtained 1,703 FortiGate source files associated with 1,689 host identifiers. "The configuration material dates to around February 2026, earlier than the likely May/June material examined in the first investigation," Hudson Rock said. The latest discovery has been codenamed FortiBleed 2.0. Institutional DNS hijacked Threat actors have used domain shadowing to place illegal gambling content beneath legitimate school and government domains in two unrelated operations. "In both cases, an unauthorized party appears to have gained access to DNS administration and created records that the original domain owners may not have noticed," Infoblox said. "Because the resulting hostnames sat within established institutional namespaces, they provided especially useful infrastructure for search-engine optimization (SEO) and traffic acquisition." One cluster, linked to a threat actor called Hidden Hawk, has been found to add individual CNAME records that mapped institutional hostnames to gambling pages hosted largely on Cloudflare Pages. The second campaign exploiting an Indian government domain "delegated entire subzones to third-party authoritative nameservers and used a wildcard, allowing many hostnames to be managed outside the victim's DNS environment." Put differently, the unauthorized DNS access creates new institutional hostnames, which resolve to infrastructure serving illegal gambling doorway pages. The pages also leverage the established reputation of school and government namespaces to ensure that the malicious URLs show up prominently in search engine results. AI banking credential warning Bank of America is reminding customers not to share banking credentials with AI agents. In an email blast to customers titled "Protecting your finances in the AI World," the financial institution urged customers to never share their username and password with another person or an outside service, "including an AI-enabled tool or agent that offers to act on your behalf." Android tightens contact access Google has announced that an upcoming Android release will no longer be able to directly write to contacts with the WRITE_CONTACTS permission. "Instead, you can use the standard contact intents (ACTION_INSERT, ACTION_EDIT, and ACTION_INSERT_OR_EDIT)," Google said. "Currently, if your app needs to save even one contact, you might be requesting WRITE_CONTACTS. But that permission grants broad access, allowing an app to make widespread changes to contacts across the device in the background, even without user interaction. Most apps don’t need such broad permission." 26,400 live credentials exposed A scan of 7.25 million public repositories on Gitee, China's largest indigenous Git hosting platform, has uncovered 26,400 unique verified-live credentials, including an active organization-admin credential for a major enterprise AI platform and thousands of live cloud provider access keys, independent security researcher Ben Zimmermann said. Critical Fortinet fixes released Fortinet has released a "coordinated set of security updates for FortiOS, FortiManager, and FortiAnalyzer" to address critical and high-severity flaws that were flagged using an AI-assisted vulnerability discovery approach. Details of the issues are being kept under wraps until November 10, 2026. With Fortinet devices becoming a favorite target for attackers, it's essential that users move quickly to apply the fixes. Zero-permission token theft Details have emerged about a now-patched flaw in Microsoft Authenticator (CVE-2026-80097 aka AuthMask) that could be exploited by installing and running a malicious application on an affected Android device and convincing the user to complete an authentication flow in the app by claiming to be a trusted app and getting the corresponding tokens. The flaw could be exploited to take over work accounts without requiring additional permissions. "Successful exploitation could allow the attacker to obtain authentication tokens and access resources as the affected user," Microsoft said. According to Enclave, "an unprivileged Android app with zero permissions could impersonate any installed Microsoft first-party app and have the Microsoft Authenticator broker hand it that app's tokens. The setup is a device with Authenticator installed and one work account signed into it." 32 fake AI bots hunt secrets Attackers are disguising themselves as AI agents to steal credentials. Cequence said it has tracked a single actor running AI agent impersonation at scale by posing as about 32 different AI bots, including ChatGPT, Claude, and Perplexity, while searching for passwords, API keys, and cloud credentials. "The malicious scanner runs from a major cloud provider and rotates through about 32 AI bot identities, spanning crawlers and assistants from OpenAI, Anthropic, Meta, Perplexity, and others," Will Glazier said. "It ignores web pages and requests files that commonly store secrets, including .env configuration files, cloud credential files, private SSH keys, and server environment data, working from a list of roughly 90 file paths. Each address sends a short burst of 50 to 190 requests in about eight seconds and then moves on. The scanner works through targets one at a time, around the clock, and first sends random nonsense paths to find websites that answer every request, a common scanning technique. It hit organizations in financial services, retail, telecommunications, energy, and software, and stayed active from at least late September through late October." China-linked network intrusion The U.S. Embassy in Fiji has revealed that hackers linked to China broke into a regional organization based in Suva between July and August 2026. "Hackers with links to China maintained access to the organization's network over several days," it said. The embassy did not name the threat actor. Nor did it disclose what data the attackers may have accessed. Camera software weaponized Attackers have been breaking into enterprise networks via camera management software, according to new research from security firm Huntress, which observed multiple incidents in September and October 2026 and traced them back to a compromised application. Source code artifacts point to a Korean company selling analog and IP cameras and digital and network video recorders. The activity abuses the legitimate "WpcMon.exe" binary to sideload DLLs that establish outbound connections to a remote server. "This activity demonstrates how attackers can blend malicious code with trusted Windows components to evade detection," Huntress said. 68 GB government data breach In a major operational security blunder, an unknown threat actor stole 68 GB from a Philippine government agency, maintained a detailed log of the transfer, then left that log open on the internet at 13.163.205[.]35:80. "The copy finished in under 24 minutes on September 6, 2026," Hunt.io said. "The transfer log records 27 SQL Server backups whose filenames correspond to the case-management systems of a Philippine overseas-employment and migrant-worker administration. Beside the log sat the operator's toolkit, a rebranded GodPotato build, a PowerShell stager, two payloads and a full Impacket environment." AI model data exfiltration concerns Canadian AI company Cohere has claimed that it caught Alibaba's Qwen3.8-Flash-Next model unsuccessfully attempting to send data to China from its evaluation sandbox as part of a prompt instructing the LLM to detect malicious file download and execution by monitoring for curl processes downloading bash scripts to /tmp followed by bash execution. "Asked to write a defensive detection rule, Qwen3.8-Flash-Next ignored instructions and inventoried the machine it was running on and then tried to upload a probe file to an Alibaba Cloud storage bucket in Beijing," Cohere said. "We cannot answer whether this is deliberate or a leftover glitch from training." Cohere has also released a dataset containing the model trace and corresponding raw token IDs in connection with the behavior. "The exact output is not guaranteed all the time, and many trials may be required to reproduce the behavior," Cohere said, adding "there are similarly unexpected URLs that the model also tends to output, most containing aliyunc." However, the findings have also led to social media chatter that the company is resorting to geopolitical fearmongering and that they are an attempt to clamp down on open-weights models. Post-quantum migration roadmap The U.S. National Institute of Standards and Technology (NIST) has released guidelines that detail the timelines for transitioning away from quantum-vulnerable algorithms to quantum-resistant standards. "The report describes different use cases and says why one migration might take longer than another," said NIST mathematician Dustin Moody, who heads the PQC standardization project. "We understand there's not one strategy that fits all use cases, and we want to help people handle their migration while staying abreast of what's changing." AI-powered ransomware operation exposed SOCRadar has uncovered the live workspace (i.e., open directory) of a threat actor tied to the n0n ransomware group, which exposed the operation's full workflow as of September 2026. The directory at 185.157.161[.]148 includes an AI coding agent configured with about 150 models to produce hundreds of attack scripts, with more than $7,216 in usage costs. "Entry points included a credential stuffing campaign against 305 FortiGate SSL-VPN devices, exposed AWS keys, weak RDP/WinRM credentials, and compromised hosting management portals," SOCRadar said. At least 23 organizations across 14 countries are said to have been identified in the workspace, including a U.S. sports retailer, a cloud provider, a teachers’ union, a Venezuelan ISP, an Argentine ministry and a pharmaceutical subsidiary. Government AI access restricted The Swedish government has barred employees from accessing browser-based versions of ChatGPT or Claude on their work computers over security concerns relating to the processing of sensitive data. "Officials were concerned that entering sensitive information into these models without an agreement setting out how to protect and secure the data could lead to it being fed into the model and stored for training," Euro News reported. 42 repositories hijacked JFrog and SafeDep have uncovered a campaign in which threat actors hijacked third-party 42 GitHub repositories across 11 owners to deploy payload blobs large enough "to evade the GitHub search and API paths normally used to find this kind of compromise." JFrog said, "The repositories contain execution hooks for AI coding assistants and IDEs, plus 12.9 to 13.7 MB polymorphic wrappers that all decode to the same hidden CI-publisher payload." The activity is assessed to be related to a Miasma-family npm worm propagated under various packages ending with "testmetest." According to SafeDep, the worm "shares code with Miasma 'Phantom Gyp' from June 2026 and adds the token-revocation wiper from Mini Shai-Hulud. The malicious versions steal credentials, spread to other packages and repositories, and install a wiper that deletes the home directory when the victim revokes the stolen GitHub token." Unsuspecting developers who installed the packages had their data stolen and repositories compromised with malicious code to produce further malicious testmetest releases and run shellpanel workflows targeting cPanel systems through CVE-2026-41940, overlapping with a prior campaign detailed by Socket in July 2026. Android banking malware-as-a-service A new Android malware operation called MR ROBOT is targeting customers of Indian banks and transforming banking fraud into a subscription business, with cybercriminals renting customized banking trojans to steal OTPs, card details, UPI PINs and credentials while secretly forwarding calls to bypass security checks. "It is not a single-actor campaign but a rented crimeware platform: a master operator leases access to affiliates, who use a Telegram bot ('APK Shield) and a web control panel (v7.0) to build personalized banking trojans on demand and distribute them through fake Play-Store-style pages and messaging-app lures," CloudSEK said. The kit impersonates around 36 lure apps, including banks, utility providers, and government services. One affiliate is estimated to have intercepted 5407 text messages from 153 infected devices. MDM platforms abused for remote access Threat actors are abusing legitimate mobile device management (MDM) platforms, like Hexnode and Rippling, by using social engineering to enroll devices or install management agents, per Huntress. "Once established, MDM provides a trusted, privileged path for malicious activity, such as deploying rogue RMM tools and maintaining remote access," it said. Critical Gotenberg RCE exploited Threat actors are exploiting CVE-2026-42589 (CVSS score: 9.8), a critical remote code execution flaw in Gotenberg, to deliver a Go-based reverse shell called "cache_base." The flaw was patched in May 2026. According to VulnCheck, the activity originated from a residential Japanese IP address in early October 2026. "The execution flow is straightforward: acquire a lock, collect host information, connect to C2, register the victim, and open a shell," VulnCheck said. Over the past 30 days, the vulnerability has recorded 1,358 exploitation events from 128 unique source IP addresses. Discord discussions go public Discord has announced it will allow search engines to index discussions in Discoverable Servers and make them accessible on the web to users outside the platform without an account or invitation, starting mid-December 2026. "Discussions in Discoverable Servers will soon be easier to find when you search the web, so you can find the answer you're looking for and step straight into the conversation on Discord," it said. The changes apply only to Discoverable Servers and do not extend to private servers and direct messages. 800+ ransomware victims claimed The Gentlemen ransomware operation has claimed more than 800 victims across multiple regions and sectors, with most attacks targeting organizations in the U.S. and Europe. "The group supports multiple platforms, with ransomware variants targeting Windows, Linux, NAS, and BSD systems, allowing its affiliates to target a broad range of enterprise environments," Acronis said. "The group's operations include the use of EDR-killing tools. In a recent incident, a custom dropper was observed deploying vulnerable Safetica ProcessMonitorDriver [CVE-2025-70795] and Lenovo BootRepair.sys drivers to terminate security processes." AI model loading RCE risk Pillar Security has disclosed an arbitrary-code-execution vulnerability in Unsloth's core model-loading path (CVE-2026-93348, CVSS score: 8.6). It has been fixed in unsloth_zoo 2026.8.14. "An attacker-controlled model configuration could cause Python code to execute during loading," researcher Ariel Fogel said. "The affected code ran inside the model-loading process, with access to whatever that process could read, modify, or authenticate to. In an AI development environment, that can include proprietary datasets, model artifacts, Hugging Face tokens, and cloud credentials. Exploitation required an affected loading path to process an attacker-controlled configuration." Unauthenticated root-level RCE XBOW said it identified an unauthenticated, critical-severity remote code execution bug in a public web application belonging to the U.S. Election Assistance Commission (EAC). "The vulnerable application was a resource/logistics calculator, not a voting machine or voter registration system," XBOW researcher Ariel Walter Garcia said. "The flaw allowed an unauthenticated attacker to execute code as root inside the backend container, with access to locally protected resources and outbound network connectivity, a privileged foothold reachable via a crafted unauthenticated web request." Session-hijacking RAT emerges A new remote access trojan called DarkCore comes with a dedicated browser that could let attackers access Gmail, WhatsApp, and MediaFire accounts using stolen sessions, while giving the impression that the activity is originating from the victim's own IP address. DarkCore was first advertised on cybercrime forums in August 2026. "The seller describes a browser that reuses those sessions to access work mailboxes, instant messaging apps, cloud storage and other services through the infected machine's IP address," BlackFog said. "The purpose is to make the access look like legitimate activity from the user." AI-powered malware framework Cisco Talos has disclosed details of a new AI-integrated command-and-control (C2) framework called NIK C2. The implant features surveillance, theft, lateral movement, and evasion capabilities, including credential dumping, RDP session hijacking, process hollowing, and a C2-driven screen lock ransomware module. "NIK C2 contains a Windows implant, using which, an actor can dump credentials, stream the victim's keystrokes to collect the targeted victim's sensitive data, and instruct an integrated AI model to analyze the harvested data, all within the compromised session," Talos said. "In this framework, the actor has abused the OpenAI Chat Completions application programming interface (API), which is an HTTP endpoint that enables ChatGPT-style conversations programmatically. In addition to the features that enable theft, an actor can also deploy desktop screen-locking ransomware via the NIK C2 implant onto the victim machine, leading to a ransom demand in Bitcoin or USDT cryptocurrencies." Three different versions of the malware have been identified to date since August 12, 2026. Talos said NIK C2 alters adversary tradecraft by collapsing collection and exploitation into a single continuous session. Malicious PDF delivers backdoor A phishing email using a FedEx tax invoice lure and containing a ZIP archive with a PDF has been observed triggering a multi-stage infection process to deliver a previously undocumented variant of the Sirius Backdoor. "The PDF abuses /OpenAction and /Launch objects to trigger an embedded Base64-encoded PowerShell command upon opening," Trellix said. "Execution relies on social engineering to trick the user into approving the PDF reader's security confirmation prompt. The PowerShell stager decrypts and reflectively loads a .NET assembly in memory. This loader performs process hollowing into legitimate Windows processes such as msbuild.exe, svchost.exe, etc., allowing the malware to operate under trusted process contexts." The final payload is SIRIUS, a Microsoft Visual C++ based backdoor with extended remote access capabilities. AI reshapes ransomware economics A new analysis from Flare has revealed that threat actors are building a mixed AI toolkit, combining commercial models with local, open-weight, and jailbroken alternatives, as well as leaning on stolen AI credentials to shift costs to victims. "Where AI can help is with understanding systems, writing tools and troubleshooting. The threat actor still needs access, decisions and a way to obtain payment," Flare said. "If AI helps an affiliate write a working data-export script without hiring a specialist, the affiliate may avoid that specialist’s fee and the wait for their help. AI makes expertise cheaper to obtain only when the cost of using and checking its work is lower than the cost of the specialist help it replaces." Emerging data-extortion threat A recently observed cyber-extortion actor named ScarlettGroup is publicly advertising alleged data compromises and uses negotiation deadlines and threatened disclosures to pressure targeted organizations. The group's dark web site listing includes victims from technology, education, government, and entertainment sectors. "ScarlettGroup demonstrates characteristics associated with financially motivated data-extortion operations, including public victim claims, deadline-based pressure, and underground forum activity," Foresiet said. "Its dedicated leak-site infrastructure and structured disclosure mechanism indicate an organized approach to promoting alleged compromises and exerting reputational pressure." Infostealers evolve into RATs Following its disruption in June 2026 as part of Operation Endgame, StealC has returned four months later as Stadia. "This time it's not a stealer: it's a full remote access trojan," Varonis said. "The RAT's features include hidden desktop control, a live command shell, a file explorer, a process manager and an in-memory loader, with StealC's stealer welded on as one module among six. The actor behind Stadia is working hard to win back original StealC customers: every former StealC customer is offered a free month on the top ($900) tier." The development comes as Moonlock Lab revealed that the Icarus macOS stealer has similarly evolved from a smash-and-grab crypto and data stealer to a malware with remote-access capabilities. The new iteration is called ICMacOS. "The stealer is actively advertised on cybercrime forums by a Russian-speaking actor operating under the handle GlowComa, with feature updates regularly announced via Telegram," SOCRadar said. "GlowComa promotes ICMacOS alongside Icarus ClickFix, a companion panel designed to deliver payloads using malicious copy-and-paste terminal commands. The infection chain relies on initial dropper scripts to detect the host architecture and harvest administrator passwords using fake system dialogs before delivering the primary payload." Another macOS-focused stealer is Aokigahara, which goes beyond browsers, VPN clients, cryptocurrency wallets, FTP/SFTP clients, password managers, and email applications to also target AI applications and development tools. "The stealer collects authentication files, session data, and configuration files associated with Claude, ChatGPT Desktop, Codex, Cursor, Windsurf, GitHub Copilot, Gemini CLI, and other tools," Check Point said. "Stolen AI credentials could offer opportunities for monetization. Usable credentials or session tokens could enable unauthorized access to paid AI services or the resale of compromised accounts." That's the week's mess. Some attacks were clever, some were painfully simple, and a few attackers made life easier for the people investigating them. The common problem? Too much trust in things nobody was watching closely. AI is adding new tricks, but the old ones aren't going anywhere. Stolen credentials, weak access controls, and forgotten bugs still get plenty of work done. New tools, familiar mistakes. The useful part is knowing where those mistakes keep showing up. That's usually where the next problem starts.

History: 22/09/2026 --- v1.0 -- Initial publication Summary On 22 September 2026, F5 published an advisory addressing a critical vulnerability affecting its BIG-IP APM product. The vendor confirmed active exploitation in the wild [1]. CERT-EU recommends taking appropriate actions as soon as possible. Technical Details The vulnerability CVE-2026-94127, with a CVSS score of 9.8, is a heap-based buffer overflow vulnerability and allow unauthenticated attacker to achieve remote code execution (RCE) on the affected device [1]. Affected Products The vulnerability affects the following versions of BIG-IP APM if configured with an access policy and an OAuth profile on a virtual server [1]: 17.1.0 - 17.1.3 17.5.0 - 17.5.1 21.1.0 Recommendations CERT-EU recommends taking the following actions as soon as possible: Preserve forensic evidence. Apply the relevant hotfix. Check for signs of compromise (see the compromise assessment section). If any sign of compromise is detected, start the incident response process. Mitigation If patching cannot be applied immediately, F5 provides an iRule-based mitigation for the affected virtual server. To obtain it, F5 BIG-IP clients should contact the F5 support [1]. Compromise Assessment CERT-EU strongly advises to look for the following indicators of compromise provided by the vendor in its advisory [1]: At a high level, multiple OAuth authentication failures, followed by suspicious commands, shortly followed by a TMM SIGABRT is the combination that should lead to human review of the system. OAuth authentication failures: check /var/log/apm for repeated occurrences of the following, especially 10 or more from a single IP in a short window. err tmm1\[30975\]: 01990004:3: : Request UserInfo from Source ID (null) IP failed. Error Code (invalid\_token) Error Description (The access token is invalid.) - Increase of OAuth failure statistics. Run the following and look for an unexplained increase in total_failed : $ tmctl global_oauth_stat -s total_requests,total_userinfo_requests,total_failed - Audit log anomalies: if OAuth failures are observed, review /var/log/audit around those timestamps for suspicious commands. TMM core files: Presence of a TMM core file alone is not an indicator, but core files should be investigated. The vendor indicates that they have observed TMM entering a loop, which causes the SOD daemon to send a SIGABRT.

Attackers exploited a previously unknown flaw in Check Point's Security Management Server in a handful of targeted attacks on July 23, the company said. The flaw, CVE-2026-93616, allows an attacker who can access the server's web service to run scripts on it without logging in. Check Point released a fix on September 22 for the server that controls firewall policies for the Check Point gateways it manages. Separately, Check Point said attackers have been trying since September 12 to exploit a VPN flaw it fixed on September 9. The attempts, against a flaw tracked as CVE-2026-85102, have targeted customers of Spark, Check Point's firewall line for small businesses. When the fix came out, Check Point had no evidence the flaw was being exploited. CVE-2026-93616 is a path traversal bug in the management server's web service. The service does not properly limit which files and folders a request can reach. An attacker can use it to upload scripts to the server and then run them. Check Point rated it 9.8 out of 10 on the CVSS scale in the CVE record for the flaw. Check Point's advisory does not name the targets of the July attacks or the attackers, nor does it say what the attackers did after exploiting the flaw. Management Server Versions and Fix Check Point numbers the Jumbo Hotfix updates for each release by "Take." Its LivePatch channel, which pushes urgent fixes, uses a separate set of take numbers. The CVE record lists these versions as affected: R82.20 with no Jumbo Hotfix installed R82.10 with Jumbo Hotfix Take 44 or below R82 with Jumbo Hotfix Take 126 or below R81.20 with Jumbo Hotfix Take 166 or below R81.10 with Jumbo Hotfix Take 190 or below (end of support) R81, R80.40, R80.30, R80.20, R80.10 and R80 (all end of support) Check Point's advisory lists R82.20 as affected without the "no Jumbo Hotfix" condition. On September 16, Check Point fixed a separate flaw in the management server, CVE-2026-91843, through LivePatch. That update was LivePatch Take 28, or Take 29 on R82.20, according to a summary of Check Point's advisory by France's CERT Santé. Check Point says those LivePatch takes do not fix CVE-2026-93616. CVE-2026-85103, a VPN certificate flaw that Check Point fixed on September 9, affected both gateways and management servers. On R82.10, R82, and R81.20, the new flaw's affected list goes one take higher than that flaw's. So a server updated only enough to be outside that September flaw's range is still affected by CVE-2026-93616. The fixed builds, and Check Point's guidance on mitigation, hunting and indicators of compromise, are in support article sk1000171. Administrators of management servers should: Check the server's release and Jumbo Hotfix take against the list above. Install the fix listed in sk1000171. Use the hunting guidance and indicators of compromise in sk1000171 to look for signs of an attack. Installing the fix does not show whether the server was attacked before. Check Point's advisory names only Security Management as affected and does not say what network access an attacker needs. The Hacker News has asked Check Point about other affected products, the fixed builds, and the July attacks. Spark Firewalls Targeted Through VPN Flaw CVE-2026-85102 is in the way Check Point gateways check certificates while a VPN connection is being set up. It may let an attacker who has not logged in run code on the gateway. Fixes have been out since September 9 and are in support article sk1000117. The affected products are Security Gateway and Spark firewalls, whether centrally or locally managed, on R81 and R81.10 (both end of support), R81.10.x, R81.20, R82, R82.00.x and R82.10. The Netherlands' National Cyber Security Centre (NCSC) says the flaw applies when these products use Site-to-Site VPN or Remote Access VPN. Check Point said the attempts came from anonymizing infrastructure, including VPN services and proxies, and used certificates with these subjects: Certificate subject: CN=vpn,OU=users,O=global Certificate subject: CN=vpn-user,OU=users,O=global Certificate subject: CN=vpnuser,OU=users,O=global The list is not complete, and other subjects may be in use. Administrators should check logs for any unusual certificate-based Mobile Access login, not only those with these subjects. They should also check what suspicious Mobile Access users do after logging in, which often includes scanning internal ports and services. Check Point says customers who installed the September 9 fix are protected, but its advisory does not say whether any attempt succeeded. For gateways that cannot be patched yet, the NCSC lists a Check Point workaround for Site-to-Site VPN: turn off the implied VPN rules and allow UDP ports 500 and 4500 only from specific peer IP addresses. The workaround does not apply to locally managed Spark firewalls. Mitigation steps from Check Point are in sk1000117.

A vulnerability in Google’s Brotli data compression library, tracked as CVE-2026-111497 and dubbed Node2Shell, has led to security updates from Microsoft, the Node.js project and the maintainers of two Python packages. Node.js and the Python packages were patched last week, and Microsoft followed on October 25 with fixes for .NET, Visual Studio and PowerShell. Bun, Envoy and Istio have also been updated. Brotli is a popular choice for compressing data sent over the web, and its decoder is embedded in a long list of applications and libraries. Described as an out-of-bounds write, the bug impacts Brotli 1.0.3 through 1.2.0. Google gave it a CVSS v4 score of 9.2, which puts it in the critical category. Brotli versions 1.0.10, 1.1.1 and 1.2.1 contain the fix. The Node.js project said specially crafted input can push data beyond the limits of a buffer used by the decoder. The resulting memory corruption could cause the process to crash or leak memory contents, and could also allow an unauthenticated attacker to run arbitrary code. Node.js credited the discovery to members of OpenAI Codex Security. According to OpenAI, the issue was uncovered during red-teaming work, after which the company notified the Brotli developers and the projects that rely on the library. OpenAI noted that the fix predates the disclosure. “This root cause issue was actually fixed in the Brotli source code in February, but it wasn’t known at the time that it gave rise to a security vulnerability and there was no more recent release of Brotli,” the AI company said. Code execution demonstrated on official Node.js image Imperva has shown that it can be exploited for code execution on the official Node.js 24.22.0 image for Linux arm64. Its researchers sent the malicious data both in a server response retrieved by the targeted application and in a request body processed by Express 5 or body-parser 2. “The proof did not succeed on every attempt. Our results establish code execution for the tested Linux arm64 build and application setups, and show how the fixed build handled the same inputs,” Imperva said. The security firm has not made its exploit public. Attacks only work if malicious Brotli data reaches the decoder, for instance through a library that unpacks compressed content on the application’s behalf. “Any application that passes attacker-controlled data to an affected Google Brotli decoder may be exposed. This includes compressed HTTP request bodies, responses fetched from untrusted servers, and compressed files,” OpenAI’s Patch the Planet initiative said in its advisory. No exploitation in the wild has been reported so far. A proof-of-concept exploit published on GitHub reportedly achieves code execution only against an intentionally weakened build, and some researchers argued the bug can only be used for denial-of-service (DoS) attacks. Microsoft products and Python packages affected Microsoft’s October 25 updates include .NET runtime versions 8.0.33, 9.0.22 and 10.0.14, along with .NET 11 Release Candidate 3. Visual Studio 2019, 2022 and 2026, as well as PowerShell 7.4, 7.5 and 7.6, have also been updated. Microsoft has categorized CVE-2026-111497 as an elevation of privilege issue with a CVSS v3.1 base score of 8.1. It rates the flaw critical for .NET and Visual Studio and important for PowerShell, and its exploitability assessment is “Exploitation More Likely.” In Python’s case, the vulnerable decoder is built into two PyPI packages, Brotli and brotlicffi. They have been patched with the release of versions 1.2.1 and 1.2.1.0, respectively. As more affected software emerged, researchers began referring to the flaw as HTTP2Shell and Broccoli2Shell. A public tracker of software that bundles its own copy of the Brotli decoder lists several projects that are still unpatched, including DuckDB, Apache Arrow, 7-Zip-zstd, p7zip and EDK II. Its maintainers say the list is incomplete, and that not every configuration of these projects necessarily exposes the vulnerable code. Applying the updates also requires restarting affected services and rebuilding container images on top of a patched base, since processes that are already running keep using the vulnerable code. Related: Mirai Botnet Operators Join PHP2Shell Attacks as ASLR Bypass Exploits Emerge Related: Attackers Exploit Third Arista VCO Zero-Day in Four Months Related: LiteLLM Compromised in Fresh Supply Chain Attack

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.*