CVE-2020-0601 — Windows CryptoAPI Spoofing Vulnerability

Executive Summary

A spoofing vulnerability exists in the way Windows CryptoAPI (Crypt32.dll) validates Elliptic Curve Cryptography (ECC) certificates. An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source. The user would have no way of knowing the file was malicious, because the digital signature would appear to be from a trusted provider. A successful exploit could also allow the attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software. The security update addresses the vulnerability by ensuring that Windows CryptoAPI completely validates ECC certificates.

Overview

8.1

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Spoofing

Released Jan 14 2020

Last Updated Jan 14 2020

Publicly Disclosed No

CISA KEV Listed (added 2021-11-03)

Known Exploits None Known

EPSS Score 0.89436 — 0.99768 percentile

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

Temporal Score: 7.3

EPSS Score

0.89436

probability of exploitation in the next 30 days

0.99768 percentile - updated 2026-06-20

View on FIRST.org

Affected Products

26 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 for 32-bit Systems	`4534306 (Security Update)`	Important	Spoofing	Yes
Windows 10 for x64-based Systems	`4534306 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1607 for 32-bit Systems	`4534271 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1607 for x64-based Systems	`4534271 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1709 for 32-bit Systems	`4534276 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4534276 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1709 for x64-based Systems	`4534276 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1803 for 32-bit Systems	`4534293 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4534293 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1803 for x64-based Systems	`4534293 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1809 for 32-bit Systems	`4534273 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4534273 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1809 for x64-based Systems	`4534273 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1903 for 32-bit Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1903 for x64-based Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1909 for 32-bit Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1909 for ARM64-based Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows 10 Version 1909 for x64-based Systems	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows Server 2016	`4534271 (Security Update)`	Important	Spoofing	Yes
Windows Server 2016 (Server Core installation)	`4534271 (Security Update)`	Important	Spoofing	Yes
Windows Server 2019	`4534273 (Security Update)`	Important	Spoofing	Yes
Windows Server 2019 (Server Core installation)	`4534273 (Security Update)`	Important	Spoofing	Yes
Windows Server, version 1803 (Server Core Installation)	`4534293 (Security Update)`	Important	Spoofing	Yes
Windows Server, version 1903 (Server Core installation)	`4528760 (Security Update)`	Important	Spoofing	Yes
Windows Server, version 1909 (Server Core installation)	`4528760 (Security Update)`	Important	Spoofing	Yes

Patches

6 patches

Article	Type	Restart
`4534306`	Security Update	Yes
`4534271`	Security Update	Yes
`4534276`	Security Update	Yes
`4534293`	Security Update	Yes
`4534273`	Security Update	Yes
`4528760`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

National Security Agency

References

MSRC Advisory MITRE NVD