Tech Optimizer
May 4, 2026
Microsoft Defender mistakenly flagged legitimate DigiCert root certificates as Trojan:Win32/Cerdigent.A!dha, leading to their removal from Windows systems globally. This issue arose after a Defender signature update on April 30th, with affected certificates including 0563B8630D62D75ABBC8AB1E4BDFB5A899B24D43 and DDFB16CD4931C973A2037D3FC83A4D7D775D05E4. The certificates were removed from the AuthRoot store under the Registry key HKLMSOFTWAREMicrosoftSystemCertificatesAuthRootCertificates. Microsoft has addressed the issue in Security Intelligence update version 1.449.430.0, which also restored the removed certificates. The false positives were linked to detections related to a recent DigiCert breach, where threat actors obtained valid code-signing certificates used for signing malware. DigiCert revoked 60 code-signing certificates, including those linked to the "Zhong Stealer" malware campaign. The malware utilized certificates issued to companies like Lenovo and Kingston, but the certificates flagged by Microsoft Defender are root certificates and do not correspond to the revoked code-signing certificates.
