Exposing Fox Tempest: A malware-signing service operation

Fox Tempest is a financially motivated threat actor that operates a malware-signing-as-a-service (MSaaS) used by other cybercriminals to more effectively distribute malicious code, including ransomware. The threat actor abuses Microsoft Artifact Signing to generate short-lived, fraudulent code-signing certificates to appear legitimately signed, allowing malware to evade security controls.

Fox Tempest has created over a thousand certificates and established hundreds of Azure tenants and subscriptions to support its operat…