Service crash via attacker-controlled heap-buffer copy
Published Oct 26, 2021 · Updated Sep 16, 2024
Heap-based buffer overflow in the CODESYS V2 web server before 1.1.9.22 allows remote attackers to crash the service via crafted requests. The FillPlcRequest path passes an attacker-controlled copy size to memcpy when moving data from a 256-byte stack buffer into a heap communication buffer. Builds from 1.1.9.20 require authentication when WebVisu user management is active; earlier builds lack that protection.
Summary
What happened
Heap-based buffer overflow in the CODESYS V2 web server before 1.1.9.22 allows remote attackers to crash the service via crafted requests. The FillPlcRequest path passes an attacker-controlled copy size to memcpy when moving data from a 256-byte stack buffer into a heap communication buffer. Builds from 1.1.9.20 require authentication when WebVisu user management is active; earlier builds lack that protection.
The record
- CVE
- CVE-2021-34583
- Published
- Oct 26, 2021
- Updated
- Sep 16, 2024
- Vendor
- CODESYS GmbH
- Product
- CODESYS Development System V2.3
- Classifications
- CWE-122, CWE-787, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 26, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 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=all web servers <V1.1.9.22
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
- Tenable CODESYS V2 web-server crash proof of conceptproof 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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