Remote Code Execution via Microsoft WinVerifyTrust Function (CVE‑2013‑3900)
What It Is
The WinVerifyTrust API, used by Windows to validate Authenticode signatures on Portable Executable (PE) files, contains a flaw that can be triggered by a maliciously crafted PE. The function may incorrectly process signature data, allowing an attacker to execute arbitrary code in the context of the calling process.
Exploitability
The vulnerability is publicly disclosed with a CVSS base score of 7.8 (High). Proof‑of‑concept code has been released, and the issue is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild.
Affected Products
- Microsoft Windows operating systems that expose the WinVerifyTrust function (all supported versions at the time of the vulnerability).
- Any application that directly invokes WinVerifyTrust for Authenticode verification.
Why It Matters for Compliance & Audit Readiness
From a control‑assurance perspective, the flaw undermines the integrity assurance control that relies on trusted code signing. Continuous control monitoring must capture evidence that code‑signing validation mechanisms are up‑to‑date and that mitigations (e.g., patch level, application whitelisting) are in place. Demonstrating timely remediation supports vendor‑management controls and provides a defensible audit trail for frameworks such as NIST CSF PR.IP‑1 (Baseline Protection) and ISO 27001 A.12.2 (Protection from Malware).
Recommended Actions
- Verify that the Microsoft security update addressing CVE‑2013‑3900 (KBxxxxxx) is applied across all Windows endpoints.
- If patching cannot be completed immediately, enforce application whitelisting or enforce strict Authenticode policy via Group Policy to block unsigned or tampered binaries.
- Update your continuous monitoring rules to flag any execution of unsigned PE files or anomalous WinVerifyTrust calls.
- Document the remediation steps in your vendor‑management and change‑control records to maintain audit readiness.
Source: https://nvd.nist.gov/vuln/detail/CVE-2013-3900