Microsoft Windows Print Spooler Privilege Escalation
CVE-2022-21999 is a medium-severity improper limitation of a pathname to a restricted directory vulnerability in Windows 10 Version 1809 from Microsoft, with a CVSS 2.0 base score of 4.6 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists version 10.0.17763.2565 as the first without the flaw, so updating Windows 10 Version 1809 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on March 25, 2022, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Windows 10 Version 1809 to 10.0.17763.2565 or a later version.
- Update Windows Server 2019 to 10.0.17763.2565 or a later version.
- Update Windows Server 2019 (Server Core installation) to 10.0.17763.2565 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 up to, but not including, 10.0.17763.2565; 10.0.0 up to, but not including, 10.0.17763.2565 | 10.0.17763.2565 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 up to, but not including, 10.0.17763.2565 | 10.0.17763.2565 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 up to, but not including, 10.0.17763.2565 | 10.0.17763.2565 |
| Microsoft | Windows 10 Version 1909 | 10.0.0 up to, but not including, 10.0.18363.2094 | 10.0.18363.2094 |
| Microsoft | Windows 10 Version 21H1 | 10.0.0 up to, but not including, 10.0.19043.1526 | 10.0.19043.1526 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 up to, but not including, 10.0.20348.524 | 10.0.20348.524 |
| Microsoft | Windows 10 Version 20H2 | 10.0.0 up to, but not including, 10.0.19042.1526 | 10.0.19042.1526 |
| Microsoft | Windows Server version 20H2 | 10.0.0 up to, but not including, 10.0.19042.1526 | 10.0.19042.1526 |
| Microsoft | Windows 11 version 21H2 | 10.0.0 up to, but not including, 10.0.22000.493 | 10.0.22000.493 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19043.0 up to, but not including, 10.0.19044.1526 | 10.0.19044.1526 |
| Microsoft | Windows 10 Version 1507 | 10.0.10240.0 up to, but not including, 10.0.10240.19204 | 10.0.10240.19204 |
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 up to, but not including, 10.0.14393.4946 | 10.0.14393.4946 |
| Microsoft | Windows Server 2016 | 10.0.14393.0 up to, but not including, 10.0.14393.4946 | 10.0.14393.4946 |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 up to, but not including, 10.0.14393.4946 | 10.0.14393.4946 |
| Microsoft | Windows 7 | 6.1.0 up to, but not including, 6.1.7601.25860 | 6.1.7601.25860 |
| Microsoft | Windows 7 Service Pack 1 | 6.1.0 up to, but not including, 6.1.7601.25860 | 6.1.7601.25860 |
| Microsoft | Windows 8.1 | 6.3.0 up to, but not including, 6.3.9600.20269 | 6.3.9600.20269 |
| Microsoft | Windows Server 2008 Service Pack 2 | 6.0.6003.0 up to, but not including, 6.0.6003.21374 | 6.0.6003.21374 |
| Microsoft | Windows Server 2008 Service Pack 2 (Server Core installation) | 6.0.6003.0 up to, but not including, 6.0.6003.21374 | 6.0.6003.21374 |
| Microsoft | Windows Server 2008 R2 Service Pack 1 | 6.1.7601.0 up to, but not including, 6.1.7601.25860 | 6.1.7601.25860 |
| Microsoft | Windows Server 2008 R2 Service Pack 1 (Server Core installation) | 6.1.7601.0 up to, but not including, 6.1.7601.25860 | 6.1.7601.25860 |
| Microsoft | Windows Server 2012 | 6.2.9200.0 up to, but not including, 6.2.9200.23605 | 6.2.9200.23605 |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 up to, but not including, 6.2.9200.23605 | 6.2.9200.23605 |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 up to, but not including, 6.3.9600.20269 | 6.3.9600.20269 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 up to, but not including, 6.3.9600.20269 | 6.3.9600.20269 |
Version data comes from the organisation that assigned the CVE; 11 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Access vector
- LocalLocal access is required.
- Access complexity
- LowNo special conditions are needed.
- Authentication
- NoneNo login is needed.
- Confidentiality
- PartialSome data can be read.
- Integrity
- PartialSome data can be modified.
- Availability
- PartialAvailability is reduced.
Vector: AV:L/AC:L/Au:N/C:P/I:P/A:P. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (microsoft.com) |
| CVSS 2.0 | 4.6 | Medium | NVD |
Official description
Windows Print Spooler Elevation of Privilege Vulnerability
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-21999US Government Resource
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 7.7 High severity
- 9.8 Critical severity
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