Microsoft Win32k Privilege Escalation
CVE-2018-8120 is a high-severity improper resource shutdown or release vulnerability in Windows Server 2008 from Microsoft, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected Windows Server 2008 versions: 32-bit Systems Service Pack 2; 32-bit Systems Service Pack 2 (Server Core installation); Itanium-Based Systems Service Pack 2, and others listed below. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on March 15, 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
- Check which version of Windows Server 2008 you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on portal.msrc.microsoft.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Windows Server 2008 | 32-bit Systems Service Pack 2; 32-bit Systems Service Pack 2 (Server Core installation); Itanium-Based Systems Service Pack 2; x64-based Systems Service Pack 2; x64-based Systems Service Pack 2 (Server Core installation) | Not stated |
| Microsoft | Windows 7 | 32-bit Systems Service Pack 1; x64-based Systems Service Pack 1 | Not stated |
| Microsoft | Windows Server 2008 R2 | Itanium-Based Systems Service Pack 1; x64-based Systems Service Pack 1; x64-based Systems Service Pack 1 (Server Core installation) | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | NVD |
| CVSS 3.1 | 7.0 | High | CISA (ADP) |
| CVSS 2.0 | 7.2 | High | NVD |
Official description
An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory, aka "Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2. This CVE ID is unique from CVE-2018-8124, CVE-2018-8164, CVE-2018-8166.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Resource Shutdown or Release
The product does not release or incorrectly releases a resource before it is made available for re-use.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.
- Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
More Improper Resource Shutdown or Release vulnerabilities (CWE-404)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- 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-2018-8120US Government Resource
Technical write-ups (may include proof of concept)
- exploit-db.com/exploits/45653/Exploit, Third Party Advisory, VDB Entry
Other vulnerabilities in Windows Server 2008
- 7.5 High severity
- 7.5 High severity
- 7.0 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
Recent Improper Resource Shutdown or Release vulnerabilities
- 7.5 High severity
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