Authentication Bypass via Malicious Certificate in Ironshield

Executive Summary

This vulnerability involves the IRONMACE Ironshield 1.0.0.167 kernel-mode driver (tvk.sys) which improperly authenticates client executables. Instead of validating PKCS signatures, it checks for hardcoded publisher and certificate strings in WIN_CERTIFICATE data. This allows local attackers to bypass authentication using crafted certificates and gain privileged IOCTL access.

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Detection Guidance

Detecting this vulnerability requires checking for the presence of the vulnerable tvk.sys driver and analyzing its behavior. Look for processes loading tvk.sys and inspect WIN_CERTIFICATE data in memory for the hardcoded strings 'IRONMACE Co., Ltd.' or 'DigiCert Trusted Root G4' without proper PKCS validation. Use tools like Process Explorer or WinObj to monitor driver loads and IOCTL interactions.

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Impact Analysis

An attacker could exploit this to execute arbitrary code with elevated privileges on your system. This may allow them to read or write kernel memory, manipulate processes, leak sensitive data like kernel pointers, or perform other malicious actions without needing admin rights or debug privileges.

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Mitigation Strategies

Immediate mitigation steps include: 1) Uninstall or disable the Ironshield driver (tvk.sys) if possible. 2) Restrict unprivileged users from executing processes that interact with the driver. 3) Monitor for suspicious IOCTL calls or unauthorized memory access. 4) Apply vendor patches if available. 5) Use endpoint detection tools to block unauthorized driver loads.

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