CVE-2010-0384 in Tor
Summary
by MITRE
Tor 0.2.2.x before 0.2.2.7-alpha, when functioning as a directory mirror, does not prevent logging of the client IP address upon detection of erroneous client behavior, which might make it easier for local users to discover the identities of clients in opportunistic circumstances by reading log files.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability described in CVE-2010-0384 affects the Tor network infrastructure by exposing client IP addresses through directory mirror logging mechanisms. This issue specifically impacts Tor versions 0.2.2.x prior to 0.2.2.7-alpha when operating in directory mirror mode. Directory mirrors serve as critical infrastructure components within the Tor network, maintaining copies of directory information that helps nodes locate and communicate with each other. When these mirrors fail to properly sanitize log entries containing client information, they inadvertently create a pathway for local attackers to discover client identities through log file analysis.
The technical flaw stems from inadequate input validation and logging practices within the Tor directory mirror implementation. When the system detects erroneous client behavior, it records this information in log files without properly anonymizing or removing client identifying information. This represents a failure in proper logging security practices and violates fundamental principles of privacy preservation in anonymous networks. The vulnerability operates under CWE-200, which addresses information exposure, and specifically demonstrates how improper logging can create information disclosure channels. The flaw is particularly concerning because it affects the core infrastructure components responsible for maintaining network directory information rather than individual client connections.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for attackers to perform correlation attacks against Tor users. Local users who gain access to the directory mirror log files can potentially reconstruct client behavior patterns and make educated guesses about user identities, especially in opportunistic scenarios where additional context is available. This weakness undermines the fundamental anonymity guarantees that Tor provides, creating a potential attack surface for adversaries who might already have local access to the mirror infrastructure. The vulnerability aligns with ATT&CK technique T1071.004, which covers application layer protocol: DNS, and demonstrates how network infrastructure can inadvertently leak sensitive information.
Mitigation strategies for this vulnerability involve upgrading to Tor version 0.2.2.7-alpha or later, which includes proper log sanitization mechanisms. System administrators should implement comprehensive logging policies that ensure client identifying information is removed or obfuscated before log entries are written to persistent storage. Additional protections include restricting local access to directory mirror systems, implementing proper file permissions on log directories, and conducting regular security audits of logging mechanisms. The fix addresses the root cause by ensuring that when erroneous client behavior is detected, the logging system strips or masks client IP addresses before writing to log files, thereby maintaining the anonymity properties that Tor is designed to preserve.