Security News > 2023 > May > Malicious Windows kernel drivers used in BlackCat ransomware attacks

The ALPHV ransomware group was observed employing signed malicious Windows kernel drivers to evade detection by security software during attacks.
The POORTRY malware is a Windows kernel driver signed using stolen keys belonging to legitimate accounts in Microsoft's Windows Hardware Developer Program.
While security software is usually protected from being terminated or tampered with, as Windows kernel drivers run with the highest privileges in the operating system, they can be used to terminate almost any process.
The new driver used by the BlackCat ransomware operation helps them elevate their privileges on compromised machines and then stop processes relating to security agents.
System administrators are recommended to use the indicators of compromise shared by Trend Micro and add the malicious drivers used by the ransomware actors to the Windows driver blocklist.
Windows admins should also ensure that 'Driver Signature Enforcement' is enabled, which blocks the installation of any drivers that do not have a valid digital signature.
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