Invalid Code Signature
Where this stands
A reviewer read the telemetry and concluded there is nothing here to detect that a sibling technique does not already cover.
AN0089's two Windows logsources are Sysmon EventID 1 ({category: process_creation, product: windows}) and PowerShell EventID 4103/4104/4105/4106 ({product: windows, service: powershell}), and neither carries a field that records whether a binary's digital signature validated. Signature fields (Signed, Signature, SignatureStatus) are real in this corpus, but only on the logsources that actually carry them: T1014 and T1068 use them on {category: driver_load, product: windows}, and T1129, T1211 and T1556.002 use them on {category: image_load, product: windows} — Sysmon EventID 6 and 7 respectively. […]
Covered instead by T1014, T1068, T1129, T1211, T1556.002, T1553.002.
What the technique is
Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with. Adversaries can copy the metadata and signature information from a signed program, then use it as a template for an unsigned program. Files with invalid code signatures will fail digital signature validation checks, but they may appear more legitimate to users and security tools may improperly handle these files. Unlike Code Signing, this activity will not result in a valid signature.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0089
Execution of binaries with invalid digital signatures, where metadata claims code is signed but validation fails. Behavior is often correlated with suspicious parent processes or unexpected execution paths.
- AN0090
Binaries or applications executed with tampered or unverifiable code signatures. Often tied to Gatekeeper bypasses, App Translocation, or use of unsigned launch daemons by untrusted users.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.