What are malicious certificates and how do attackers use them?

Digital security certificates play a critical role in modern IT infrastructure, confirming the authenticity of websites, software, and code publishers. However, attacker arsenals frequently incorporate methods for compromising or illegitimately obtaining such certificates to bypass security systems. Malicious software signed with a valid digital certificate from a legitimate company is much more likely to be allowed through by security software and the operating system without displaying warnings to the user.

Attackers obtain certificates through several methods, including hacking certificate authority infrastructure, stealing private keys from software developers, or registering shell companies to pass simplified verification. Once they have a signed executable file, cybercriminals inject it into legitimate distributions or use it to orchestrate targeted attacks. Because the operating system trusts the publisher, built-in integrity and file reputation control mechanisms do not block the dangerous application from running.

To minimize the risks associated with the use of forged or stolen certificates by attackers, modern antivirus solutions employ heuristic analysis and reputation databases. Security professionals constantly monitor certificate revocation lists and analyze digital signatures for anomalies. System administrators are advised to strictly restrict root certificate installation rights in operating systems and use modern application control tools that block the execution of unauthorized software regardless of whether a signature is present.