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CVE-2023-36033Exploited in the wildNVD status: Analyzed

Microsoft Windows Desktop Window Manager (DWM) Core Library Privilege Escalation

CVE-2023-36033 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in Windows 10 Version 1809 from Microsoft, with a CVSS 3.1 base score of 7.8 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. The record lists version 10.0.17763.5122 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 November 14, 2023, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Windows 10 Version 1809 to 10.0.17763.5122 or a later version.
  2. Update Windows Server 2019 to 10.0.17763.5122 or a later version.
  3. Update Windows Server 2019 (Server Core installation) to 10.0.17763.5122 or a later version.
  4. CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  5. Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
MicrosoftWindows 10 Version 180910.0.17763.0 up to, but not including, 10.0.17763.5122; 10.0.0 up to, but not including, 10.0.17763.512210.0.17763.5122
MicrosoftWindows Server 201910.0.17763.0 up to, but not including, 10.0.17763.512210.0.17763.5122
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 up to, but not including, 10.0.17763.512210.0.17763.5122
MicrosoftWindows Server 202210.0.20348.0 up to, but not including, 10.0.20348.211310.0.20348.2113
MicrosoftWindows 11 version 21H210.0.0 up to, but not including, 10.0.22000.260010.0.22000.2600
MicrosoftWindows 10 Version 21H210.0.19043.0 up to, but not including, 10.0.19043.369310.0.19043.3693
MicrosoftWindows 11 version 22H210.0.22621.0 up to, but not including, 10.0.22621.271510.0.22621.2715
MicrosoftWindows 10 Version 22H210.0.19045.0 up to, but not including, 10.0.19045.369310.0.19045.3693
MicrosoftWindows 11 version 22H310.0.22631.0 up to, but not including, 10.0.22631.271510.0.22631.2715
MicrosoftWindows 11 Version 23H210.0.22631.0 up to, but not including, 10.0.22631.271510.0.22631.2715
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 up to, but not including, 10.0.25398.53110.0.25398.531
MicrosoftWindows 10 1809before 10.0.17763.512210.0.17763.5122
MicrosoftWindows 10 21h2before 10.0.19041.369310.0.19041.3693
MicrosoftWindows 10 22h2before 10.0.19045.369310.0.19045.3693
MicrosoftWindows 11 21h2before 10.0.22000.260010.0.22000.2600
MicrosoftWindows 11 22h2before 10.0.22621.271510.0.22621.2715
MicrosoftWindows 11 23h2before 10.0.22621.271510.0.22621.2715
MicrosoftWindows Server 2022 23h2before 10.0.25398.53110.0.25398.531

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
LowNo special conditions are needed; the attack works reliably.
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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA (microsoft.com)
CVSS 3.17.8HighNVD

Official description

Windows DWM Core Library 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.

More Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities (CWE-119)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities

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