Threats / Microsoft / CVE-2013-3900
CVE-2013-3900
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft WinVerifyTrust function vulnerability
WinVerifyTrust function improperly validates Windows Authenticode signatures on PE files, allowing remote code execution through malicious signed binaries.
Verdict
Today item — known-exploited.
A remote code execution vulnerability in Microsoft's WinVerifyTrust function fails to properly validate Authenticode signatures on portable executable files. Attackers can exploit this to execute arbitrary code by distributing specially crafted signed binaries that bypass signature verification chec
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
12 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-01-10).
Probability (EPSS)
EPSS 0.44647 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, WinVerifyTrust function. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
Craft a malicious PE file with a forged or improperly validated Authenticode signature that passes WinVerifyTrust verification.
Business
Malware distribution infrastructure gains a trusted delivery vector, increasing infection rates and reducing detection by signature-based security controls.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
Distribute the malicious signed binary through legitimate channels or watering hole attacks to reach target systems.
Business
Enterprise endpoints execute untrusted code with system privileges, compromising confidentiality, integrity, and availability of critical business systems.
3
Lateral reach — past segmentation narrative 3
Attacker
Establish persistent access or lateral movement within compromised networks using the code execution capability.
Business
Attackers gain foothold for data exfiltration, ransomware deployment, or supply chain compromise affecting downstream customers and partners.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05