Firewall bypass via unchecked token impersonation level
Published Jun 8, 2021 · Updated Aug 3, 2024
Authorization bypass in the Windows TCP/IP Driver allows local users on affected Windows releases to bypass firewall rules. The Windows Filtering Platform fails to require SecurityImpersonation level before using a captured impersonation token for filter access checks. A low-privileged local process can create a socket under the captured system token and perform network operations blocked by firewall policy.
Summary
What happened
Authorization bypass in the Windows TCP/IP Driver allows local users on affected Windows releases to bypass firewall rules. The Windows Filtering Platform fails to require SecurityImpersonation level before using a captured impersonation token for filter access checks. A low-privileged local process can create a socket under the captured system token and perform network operations blocked by firewall policy.
The record
- CVE
- CVE-2021-31970
- Published
- Jun 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-639, T1562.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 8, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.0 <10.0.10240.18967
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Windows Filtering Platform token access-check proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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