CVE-2022-23643 in Sourcegraph
Summary
by MITRE • 02/16/2022
Sourcegraph is a code search and navigation engine. Sourcegraph versions 3.35 and 3.36 reintroduced a previously fixed side-channel vulnerabilitity in the Code Monitoring feature where strings in private source code could be guessed by an authenticated but unauthorized actor. This issue affects only the Code Monitoring feature, whereas CVE-2021-43823 also affected saved searches. A successful attack would require an authenticated bad actor to create many Code Monitors to receive confirmation that a specific string exists. This could allow an attacker to guess formatted tokens in source code, such as API keys. This issue was patched in versions 3.35.2 and 3.36.3 of Sourcegraph. Those who are unable to upgrade may disable the Code Monitor feature in their installation.
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Analysis
by VulDB Data Team • 02/18/2022
The vulnerability CVE-2022-23643 represents a side-channel attack within Sourcegraph's Code Monitoring feature that emerged in versions 3.35 and 3.36 following a regression from previously addressed security measures. This weakness specifically targets the code search and navigation engine's monitoring capabilities where unauthorized authenticated users could potentially infer sensitive information from private source code repositories. The vulnerability operates through a sophisticated timing-based attack vector that allows malicious actors to deduce the presence of specific string patterns within code files by creating multiple monitoring requests and observing response patterns. Such an attack requires the adversary to be authenticated to the system but not authorized to access the target repositories, creating a significant privilege escalation risk within the codebase access controls.
The technical implementation of this side-channel vulnerability stems from insufficient input validation and response timing variations in the Code Monitoring feature's processing logic. When an authenticated user creates multiple code monitors targeting specific string patterns, the system's response behavior varies based on whether the target string exists within the monitored codebase. This timing differential creates a covert channel through which an attacker can perform statistical analysis to determine string existence, effectively enabling code content inference without direct access permissions. The vulnerability aligns with CWE-203: "Information Exposure Through Discrepancy" and represents a classic example of how seemingly benign functionality can create security risks through information leakage mechanisms. The attack methodology involves creating numerous monitoring queries and correlating response times to confirm string presence, making it particularly dangerous for discovering sensitive tokens, API keys, or other credential information embedded within source code.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the trust model within Sourcegraph's access control system. Attackers with authenticated but unauthorized access can systematically enumerate sensitive code elements, potentially compromising entire development environments and exposing critical infrastructure credentials. This threat is particularly severe in organizations where code repositories contain production secrets, configuration data, or other sensitive information that should remain protected even from authenticated users who lack proper authorization. The vulnerability affects only the Code Monitoring feature while leaving other Sourcegraph components like saved searches unaffected, though this partial scope does not diminish the severity of the exposure. According to ATT&CK framework, this vulnerability maps to T1566.001: "Phishing: Spearphishing Attachment" and T1078: "Valid Accounts" as it exploits legitimate authentication mechanisms to gain unauthorized information access through legitimate system features.
Mitigation strategies for CVE-2022-23643 involve immediate patching to versions 3.35.2 or 3.36.3 where the vulnerability has been properly addressed through enhanced input validation and response normalization. Organizations unable to upgrade immediately should disable the Code Monitoring feature entirely to prevent exploitation while maintaining system functionality. Security teams should implement monitoring for unusual code monitoring activity patterns that might indicate attempted exploitation, particularly focusing on users creating multiple concurrent monitors targeting similar string patterns. The fix addresses the core timing discrepancies in the system's response handling and implements proper access controls that prevent unauthorized inference of code content through monitoring operations. Additionally, organizations should conduct comprehensive security reviews of their code monitoring configurations and implement principle of least privilege controls to minimize the potential impact of similar vulnerabilities in other system components. Regular security assessments should include verification of proper input sanitization and response consistency mechanisms to prevent similar side-channel attack vectors from emerging in other features.