basicsecurity.net
Proof, not just disclosure.
Threats / Microsoft / CVE-2020-1464
CVE-2020-1464 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Windows vulnerability

Microsoft Windows contains a spoofing vulnerability in file signature validation, allowing attackers to bypass security features and load improperly signed files.

Verdict

Today item — known-exploited.

This signature validation bypass enables code execution and security feature circumvention. The vulnerability has been exploited in the wild, though not as part of ransomware campaigns. Exploitation requires local or network access to place malicious files.

CISA KEV Yes · 2021-11-033EPSS 0.41131 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
4 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 2021-11-03).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.41131 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-347 CWE-347 — weakness family: Cryptography.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-347 · CWE-347Cryptography
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution 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 board
1

Front door — unauthenticated access narrative 1

Attacker
I craft a malicious file and bypass Windows signature validation checks to make it appear legitimate.
Business
Attackers gain ability to execute unauthorized code and disable security protections, increasing breach risk.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I load improperly signed executables that Windows fails to reject due to the validation flaw.
Business
Malware and unauthorized software can execute with system privileges, compromising endpoint integrity.
3

Lateral reach — past segmentation narrative 3

Attacker
I exploit this to bypass code signing requirements and security policy enforcement mechanisms.
Business
Organizations lose control over which software runs on Windows systems, enabling lateral movement and persistence.
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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • 4 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Catalogued by microsoft (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by microsoftCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.