Destination hostname disclosure via inverted SafeSocks logic
Published Jan 14, 2023 · Updated Apr 7, 2025
Protection mechanism failure in Tor before 0.4.7.13 allows attackers to expose destination hostnames through unsafe SOCKS4 traffic. The SafeSocks protocol check reverses its SOCKS4 and SOCKS4a decisions, accepting client-resolved SOCKS4 requests while rejecting proxy-resolved SOCKS4a requests. Exposure requires SafeSocks to be enabled and a client application to use SOCKS4; the resulting local DNS lookup can reveal the requested hostname outside Tor.
Summary
What happened
Protection mechanism failure in Tor before 0.4.7.13 allows attackers to expose destination hostnames through unsafe SOCKS4 traffic. The SafeSocks protocol check reverses its SOCKS4 and SOCKS4a decisions, accepting client-resolved SOCKS4 requests while rejecting proxy-resolved SOCKS4a requests. Exposure requires SafeSocks to be enabled and a client application to use SOCKS4; the resulting local DNS lookup can reveal the requested hostname outside Tor.
The record
- CVE
- CVE-2023-23589
- Published
- Jan 14, 2023
- Updated
- Apr 7, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-693
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 14, 2023CVE publishedPublication date reported by the CVE source.
- Apr 7, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
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
- Tor issue 40730 SafeSocks proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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