Security News > 2023 > July > Hackers exploit Windows policy to load malicious kernel drivers

Microsoft blocked code signing certificates predominantly used by Chinese hackers and developers to sign and load malicious kernel mode drivers on breached systems by exploiting a Windows policy loophole.

With Windows Vista, Microsoft introduced policy changes restricting how Windows kernel-mode drivers could be loaded into the operating system, requiring developers to submit their drivers for review and sign them through Microsoft's developer portal.

A new report by Cisco Talos explains that Chinese threat actors are exploiting the third policy by using two open-source tools, 'HookSignTool' and 'FuckCertVerify,' to alter the signing date of malicious drivers before July 29th, 2015.

By altering the signing date, the threat actors can use older, leaked, non-revoked certificates to sign their drivers and load them into Windows for privilege escalation.

Cisco's researchers have found more than a dozen certificates in GitHub repositories and Chinese-language forums that can be used by these tools, which are widely used for game cracks that can bypass DRM checks and malicious kernel drivers.

Malicious Windows kernel drivers used in BlackCat ransomware attacks.

News URL

https://www.bleepingcomputer.com/news/security/hackers-exploit-windows-policy-to-load-malicious-kernel-drivers/