Microsoft says it has disrupted a malware-signing-as-a-service (MSaaS) operation that abused the company's Artifact Signing service to generate fraudulent code-signing certificates used by ransomware gangs and other cybercriminals. According to a report published today by Microsoft Threat Intelligence, the threat actor tracked as Fox Tempest used the Microsoft Artifact Signing platform to create short-lived certificates that allowed malware to be digitally signed and trusted as legitimate software by both users and operating systems. Azure Artifact Signing (previously Trusted Signing) is a cloud-based service launched by Microsoft in 2024 that allows developers to easily have their programs signed by Microsoft. Microsoft says the financially motivated threat actor created more than 1,000…