Server hang via zero-length packet parsing loop
Published Oct 3, 2023 · Updated Sep 20, 2024
Infinite-loop denial of service in FreeOpcUa asyncua before 0.9.96 allows remote attackers to hang a server with a malformed packet. In data_received, a zero-size secure-message header produces a negative body size, so buffer slicing advances by zero and the receive loop reprocesses the same bytes. An unauthenticated TCP connection to an exposed OPC UA server is sufficient; the loop consumes memory and interrupts service.
Summary
What happened
Infinite-loop denial of service in FreeOpcUa asyncua before 0.9.96 allows remote attackers to hang a server with a malformed packet. In data_received, a zero-size secure-message header produces a negative body size, so buffer slicing advances by zero and the receive loop reprocesses the same bytes. An unauthenticated TCP connection to an exposed OPC UA server is sufficient; the loop consumes memory and interrupts service.
The record
- CVE
- CVE-2023-26151
- Published
- Oct 3, 2023
- Updated
- Sep 20, 2024
- Vendor
- FreeOpcUa
- Product
- asyncua
- Classifications
- CWE-835, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 3, 2023CVE publishedPublication date reported by the CVE source.
- Sep 20, 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=0 <0.9.96
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
- Zero-size OPC UA packet proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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