Signer reputation is a trust score or risk signal that security platforms use to evaluate software signed with a certificate. It considers factors such as the certificate age, publisher history, prior detections, revocation status, and how often the signer appears in benign or malicious samples. A good reputation can make signed software more likely to run smoothly, while a poor reputation can trigger warnings, extra scrutiny, or blocking.
This matters because code signing is meant to prove origin and integrity, but criminals can abuse that trust by stealing certificates or using signing services to make malware look legitimate. In practice, defenders use signer reputation in allowlisting, browser and endpoint protections, and email or download filters to reduce risk. Attackers try to poison or bypass it so their binaries are treated as normal software long enough to execute and establish persistence. Signer reputation is therefore a defense layer, not a guarantee of safety.