CVE-2013-3900
WinVerifyTrust Signature Validation Vulnerability
Description
Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update the Security Updates table and to inform customers that the EnableCertPaddingCheck is available in all currently supported versions of Windows 10 and Windows 11. While the format is different from the original CVE published in 2013, except for clarifications about how to configure the EnableCertPaddingCheck registry value, the information herein remains unchanged from the original text published on December 10, 2013, Microsoft does not plan to enforce the stricter verification behavior as a default functionality on supported releases of Microsoft Windows. This behavior remains available as an opt-in feature via reg key setting, and is available on supported editions of Windows released since December 10, 2013. This includes all currently supported versions of Windows 10 and Windows 11. The supporting code for this reg key was incorporated at the time of release for Windows 10 and Windows 11, so no security update is required; however, the reg key must be set. See the Security Updates table for the list of affected software. Vulnerability Description A remote code execution vulnerability exists in the way that the WinVerifyTrust function handles Windows Authenticode signature verification for portable executable (PE) files. An anonymous attacker could exploit the vulnerability by modifying an existing signed executable file to leverage unverified portions of the file in such a way as to add malicious code to the file without invalidating the signature. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Exploitation of this vulnerability requires that a user or application run or install a specially crafted, signed PE file. An attacker could modify an... See more at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2013-3900
In plain language
AI Act nowCVE-2013-3900 is a Windows weakness where a specially made “signed-looking” file can run malicious code on your PC when someone gets you to open or install it; most small businesses only need to worry if users can be tricked into running a crafted file (it’s not a normal internet attack).
CVE-2013-3900 is a signature-validation flaw (CWE-347) in Windows where crafted, Authenticode-signed PE files can be executed without invalidating the signature when WinVerifyTrust is used, leading to arbitrary code execution under the privileges of the user who runs the modified file.
What to do now
- Check whether the Windows devices in your business include Windows 10, Windows 11, or any of the listed Windows Server versions.
- On affected machines, apply the Microsoft guidance for CVE-2013-3900 (Microsoft Security Update Guide) and ensure the mitigation/setting is enabled as described.
- Verify the registry-based “EnableCertPaddingCheck” protection is set to the required value on systems where this opt-in protection is used.
- Update and patch all Windows endpoints promptly using Microsoft’s instructions for this CVE, then re-check the mitigation remains enabled after updates.
CVSS Vector Breakdown
AV:LAttack VectorAC:LAttack ComplexityPR:NPrivileges RequiredUI:RUser InteractionS:UScopeC:NConfidentialityI:HIntegrityA:NAvailabilityWeaknesses
Affected Products
Exploitability
Required action: Apply updates per vendor instructions.
Attack Graph
Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.
MITRE ATT&CK
1 techniqueReferences
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