System code execution via unchecked section offset
Published Jun 8, 2021 · Updated Aug 3, 2024
Heap buffer overflow in Microsoft Malware Protection Engine before 1.1.18200.3 allows attackers to execute code via a crafted file. The CEmbededDLLDumper::GenerateDLL function trusts an AsProtect section RVA when computing a memory-copy destination, allowing controlled data, size, and offset to overwrite heap memory. A victim must cause Defender to scan the file; successful exploitation runs code as NT AUTHORITY\SYSTEM.
Summary
What happened
Heap buffer overflow in Microsoft Malware Protection Engine before 1.1.18200.3 allows attackers to execute code via a crafted file. The CEmbededDLLDumper::GenerateDLL function trusts an AsProtect section RVA when computing a memory-copy destination, allowing controlled data, size, and offset to overwrite heap memory. A victim must cause Defender to scan the file; successful exploitation runs code as NT AUTHORITY\SYSTEM.
The record
- CVE
- CVE-2021-31985
- Published
- Jun 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- Microsoft
- Product
- Microsoft Malware Protection Engine
- Classifications
- T1203
- Attack vector
- local
- Privileges
- unauthenticated
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=1.1.0.0 <Version 1.1.18200.3
What conditions does exploitation require?
What is affected?
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
- PixiePoint AsProtect heap-overflow exploitfunctional · demonstrated
- Project Zero AsProtect crash triggerproof 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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