Proxy crash via truncated chunked response
Published Mar 9, 2021 · Updated Aug 3, 2024
Out-of-bounds read in Privoxy before 3.0.32 allows remote attackers to crash the proxy via a truncated chunked HTTP response. The chunked_body_is_complete() parser advances past declared chunk data and compares the next two bytes with CRLF without first ensuring that both bytes remain in the input buffer. Exploitation requires a response that reaches the proxy's chunked-body parser; successful exploitation interrupts proxy service without reported data disclosure or modification.
Summary
What happened
Out-of-bounds read in Privoxy before 3.0.32 allows remote attackers to crash the proxy via a truncated chunked HTTP response. The chunked_body_is_complete() parser advances past declared chunk data and compares the next two bytes with CRLF without first ensuring that both bytes remain in the input buffer. Exploitation requires a response that reaches the proxy's chunked-body parser; successful exploitation interrupts proxy service without reported data disclosure or modification.
The record
- CVE
- CVE-2021-20275
- Published
- Mar 9, 2021
- Updated
- Aug 3, 2024
- Vendor
- Privoxy Developers
- Product
- Privoxy
- Classifications
- CWE-119, CWE-125, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 9, 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?
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- Affected versionversion=privoxy 3.0.32
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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