CVE-2010-0486 in Windows
Summary
by MITRE
The WinVerifyTrust function in Authenticode Signature Verification 5.1, 6.0, and 6.1 in Microsoft Windows 2000 SP4, Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista Gold, SP1, and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 does not properly use unspecified fields in a file digest, which allows user-assisted remote attackers to execute arbitrary code via a modified (1) Portable Executable (PE) or (2) cabinet (aka .CAB) file that incorrectly appears to have a valid signature, aka "WinVerifyTrust Signature Validation Vulnerability."
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Analysis
by VulDB Data Team • 03/17/2021
The CVE-2010-0486 vulnerability represents a critical flaw in Microsoft Windows Authenticode signature verification mechanisms that affects multiple operating system versions from Windows 2000 through Windows 7. This vulnerability resides within the WinVerifyTrust function which is responsible for validating digital signatures on executable files and other components. The flaw stems from improper handling of unspecified fields within file digest calculations, creating a window where malicious actors can manipulate signature validation processes without detection.
The technical implementation of this vulnerability exploits the way Windows processes cryptographic hashes during signature verification. When a file is signed with Authenticode, the system computes a digest of the file content and compares it against the signature's expected hash value. However, the WinVerifyTrust function fails to properly validate certain unspecified fields within the digest structure, allowing attackers to modify PE or CAB files while maintaining what appears to be a valid signature. This occurs because the verification process does not adequately check all components of the cryptographic hash structure, leaving gaps that can be exploited.
From an operational perspective, this vulnerability creates a significant attack surface for remote code execution scenarios. Attackers can craft malicious files that appear legitimate to Windows signature verification systems, bypassing security controls that rely on digital signatures for trust decisions. The user-assisted nature of this attack means that victims must open or execute the malicious file, but the attack can be delivered through various vectors including email attachments, malicious downloads, or compromised websites. The impact extends beyond simple code execution to potentially allow privilege escalation and system compromise when combined with other exploitation techniques.
The vulnerability maps directly to CWE-254 in the Common Weakness Enumeration, which describes "Security Features" weaknesses related to improper implementation of security controls. Additionally, this vulnerability aligns with ATT&CK technique T1553.002, "Subvert Trust Controls: Code Signing," which focuses on bypassing code signing validation mechanisms. The attack chain typically involves creating a modified file with a valid signature, delivering it to a target system, and executing it with elevated privileges. Organizations using affected Windows versions face significant risk as the vulnerability affects core operating system components that are fundamental to system security.
Mitigation strategies for CVE-2010-0486 include immediate deployment of Microsoft security updates that address the signature verification flaw, implementation of additional security controls such as application whitelisting, and regular monitoring for suspicious file execution patterns. System administrators should also consider disabling unnecessary code signing validation where appropriate and implementing comprehensive endpoint protection solutions that can detect anomalous behavior patterns. The vulnerability underscores the importance of maintaining up-to-date security patches and demonstrates how cryptographic implementation flaws can create persistent security risks that affect multiple system generations.