Windows Defender Application Control Security Feature Bypass Vulnerability (CVE-2020-0951)
Published Sources: CVE.org, OSV
What is affected, what to do
<p>A security feature bypass vulnerability exists in Windows Defender Application Control (WDAC) which could allow an attacker to bypass WDAC enforcement. An attacker who successfully exploited this vulnerability could execute PowerShell commands that would be blocked by WDAC.</p> <p>To exploit the vulnerability, an attacker need administrator access on a local machine where PowerShell is running.
Update Microsoft PowerShell 7.0 to version 7.0.8, Microsoft PowerShell 7.1 to version 7.1.5.
- Affected
- Microsoft Windows 10 Version 1803
gte 10.0.0..* - Microsoft Windows 10 Version 1809
gte 10.0.0..* - Microsoft Windows Server 2019
gte 10.0.0..* - Microsoft Windows Server 2019 (Server Core installation)
gte 10.0.0..* - Microsoft Windows 10 Version 1909
gte 10.0.0..* - Microsoft Windows Server, version 1909 (Server Core installation)
gte 10.0.0..* - Microsoft Windows 10 Version 1709 for 32-bit Systems
gte 10.0.0..* - Microsoft Windows 10 Version 1709
gte 10.0.0..* - Microsoft Windows 10 Version 1903 for 32-bit Systems
gte 10.0.0..* - Microsoft Windows 10 Version 1903 for x64-based Systems
gte 10.0.0..* - Microsoft Windows 10 Version 1903 for ARM64-based Systems
gte 10.0.0..* - Microsoft Windows Server, version 1903 (Server Core installation)
gte 10.0.0..* - Microsoft Windows 10 Version 2004
gte 10.0.0..* - Microsoft Windows Server version 2004
gte 10.0.0..* - Microsoft Windows 10 Version 1607
gte 10.0.0..* - Microsoft Windows Server 2016
gte 10.0.0..* - Microsoft Windows Server 2016 (Server Core installation)
gte 10.0.0..* - Microsoft PowerShell 7.0
lt 7.0.0..7.0.8 - Microsoft PowerShell 7.1
lt 7.1.0..7.1.5
- Microsoft Windows 10 Version 1803
- Fixed in
- Microsoft PowerShell 7.0
7.0.8 - Microsoft PowerShell 7.1
7.1.5
- Microsoft PowerShell 7.0
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
6.7
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
6.7
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: CVE.org, OSV
6.6 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 93.8
Show all metrics
- Severity
- Medium
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 103.89 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 6.7 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 6.7
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 6.6 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 93.8
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
<p>A security feature bypass vulnerability exists in Windows Defender Application Control (WDAC) which could allow an attacker to bypass WDAC enforcement. An attacker who successfully exploited this vulnerability could execute PowerShell commands that would be blocked by WDAC.</p> <p>To exploit the vulnerability, an attacker need administrator access on a local machine where PowerShell is running. The attacker could then connect to a PowerShell session and send commands to execute arbitrary code.</p> <p>The update addresses the vulnerability by correcting how PowerShell commands are validated when WDAC protection is enabled.</p>
Source: NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Microsoft | PowerShell 7.0 |
|
|
| Microsoft | PowerShell 7.1 |
|
|
| microsoft | powershell |
|
|
Distribution and container packages (3)
Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.
| Affected versions | Fixed in | ||
|---|---|---|---|
| bitnami | powershell |
|
|
Vendors and products
- Microsoft Microsoft PowerShell
- Microsoft Powershell 7.0
- Microsoft Powershell 7.1
- Microsoft Microsoft Windows 10
- Microsoft Windows 10 Version 1607
- Microsoft Windows 10 Version 1709
- Microsoft Windows 10 Version 1709 For 32-bit Systems
- Microsoft Windows 10 Version 1803
- Microsoft Windows 10 Version 1809
- Microsoft Windows 10 Version 1903 For 32-bit Systems
- Microsoft Windows 10 Version 1903 For Arm64-based Systems
- Microsoft Windows 10 Version 1903 For X64-based Systems
Affected operating systems
| Windows | Microsoft | Windows 10 Version 1607 | — |
| Windows | Microsoft | Windows 10 Version 1709 | 1709 |
| Windows | Microsoft | Windows 10 Version 1709 for 32-bit Systems | 1709 |
| Windows | Microsoft | Windows 10 Version 1803 | — |
| Windows | Microsoft | Windows 10 Version 1809 | — |
| Windows | Microsoft | Windows 10 Version 1903 for 32-bit Systems | 1903 |
| Windows | Microsoft | Windows 10 Version 1903 for ARM64-based Systems | 1903 |
| Windows | Microsoft | Windows 10 Version 1903 for x64-based Systems | 1903 |
| Windows | Microsoft | Windows 10 Version 1909 | — |
| Windows | Microsoft | Windows 10 Version 2004 | — |
| Windows | Microsoft | Windows Server 2016 | — |
| Windows | Microsoft | Windows Server 2016 (Server Core installation) | — |
| Windows | Microsoft | Windows Server 2019 | — |
| Windows | Microsoft | Windows Server 2019 (Server Core installation) | — |
| Windows | Microsoft | Windows Server version 2004 | — |
| Windows | Microsoft | Windows Server, version 1903 (Server Core installation) | — |
| Windows | Microsoft | Windows Server, version 1909 (Server Core installation) | — |
| Windows | microsoft | windows_10 | 1607 |
| Windows | microsoft | windows_10 | 1709 |
| Windows | microsoft | windows_10 | 1803 |
| Windows | microsoft | windows_10 | 1809 |
| Windows | microsoft | windows_10 | 1903 |
| Windows | microsoft | windows_10 | 1909 |
| Windows | microsoft | windows_10 | 2004 |
References & sources
- NVD (NIST)vuln/detail/CVE-2020-0951web
- portal.msrc.microsoft.comen-US/security-guidance/advisory/CVE-2020-0951web, x_refsource_MISC, Patch, Vendor advisory
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<a href="https://intel.neosec.eu/en/cve/CVE-2020-0951"><img src="https://intel.neosec.eu/badge/cve/CVE-2020-0951.svg?lang=en" alt="CVE-2020-0951 – NEOSEC Intel" height="20"></a>