Stay updated on certificate-related infosec topics, including SSL/TLS, PKI, and digital certificate management for robust cyber security.
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Background for this topic.
Digital certificates are electronic documents that verify the ownership of a public cryptographic key by an individual, organization, or device. Issued by trusted Certificate Authorities (CAs) within a Public Key Infrastructure (PKI), certificates enable secure communication by confirming identities and supporting encryption protocols like TLS. They include information such as the subject’s name, public key, issuer, validity period, and digital signature from the CA.
Security concerns with certificates focus on risks like CA compromise or fraudulent issuance, which can allow attackers to impersonate legitimate entities and intercept or alter encrypted traffic. Expired or revoked certificates may cause connection failures or be exploited if clients do not properly validate them. Effective certificate lifecycle management—including timely renewal, revocation checking (via CRLs or OCSP), and monitoring for unauthorized certificates—is essential to maintaining trust and preventing man-in-the-middle attacks or unauthorized access.
Microsoft revoked more than 200 digital certificates that threat actors used to sign fake Teams binaries that set the stage for Rhysida ransomware attacks.