Microsoft Win32k Privilege Escalation
CVE-2015-2360 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in Windows 7 from Microsoft, with a CVSS 2.0 base score of 7.2 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. CISA added it to the Known Exploited Vulnerabilities catalogue on May 25, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Windows 7 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 docs.microsoft.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Windows 7 | Not specified in the record | Not stated |
| Microsoft | Windows 8 | Not specified in the record | Not stated |
| Microsoft | Windows 8.1 | Not specified in the record | Not stated |
| Microsoft | Windows Rt | Not specified in the record | Not stated |
| Microsoft | Windows Rt 8.1 | Not specified in the record | Not stated |
| Microsoft | Windows Server 2003 | r2 | Not stated |
| Microsoft | Windows Server 2008 | r2 | Not stated |
| Microsoft | Windows Server 2012 | r2 | Not stated |
| Microsoft | Windows Vista | Not specified in the record | Not stated |
Version data comes from NVD's product matching. 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
- CompleteAll data can be read.
- Integrity
- CompleteAny data can be modified.
- Availability
- CompleteThe system can be shut down completely.
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 7.2 | High | NVD |
Official description
win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2 and R2 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows local users to gain privileges or cause a denial of service (memory corruption) via a crafted application, aka "Win32k Elevation of Privilege Vulnerability."
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
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, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
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-2015-2360US Government Resource
Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities
- 10.0 High severity
Adobe Flash Player Dereferenced Pointer Exploited
- 9.3 High severity
- 8.8 High severity
- 7.8 High severity
Microsoft Win32k Privilege Escalation Exploited
- 7.5 High severity
Adobe Flash Player Memory Corruption Exploited
- 9.8 Critical severity
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