CVE-2024-6873 in ClickHouse
Summary
by MITRE • 08/01/2024
It is possible to crash or redirect the execution flow of the ClickHouse server process from an unauthenticated vector by sending a specially crafted request to the ClickHouse server native interface. This redirection is limited to what is available within a 256-byte range of memory at the time of execution, and no known remote code execution (RCE) code has been produced or exploited.
Fixes have been merged to all currently supported version of ClickHouse. If you are maintaining your own forked version of ClickHouse or using an older version and cannot upgrade, the fix for this vulnerability can be found in this commit https://github.com/ClickHouse/ClickHouse/pull/64024 .
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Analysis
by VulDB Data Team • 08/01/2024
The vulnerability identified as CVE-2024-6873 represents a significant security flaw in the ClickHouse database server that allows unauthenticated attackers to disrupt service execution through carefully constructed native protocol requests. This issue affects the server's native interface, which serves as the primary communication channel for database operations, making it a critical vector for potential disruption attacks. The vulnerability stems from inadequate input validation within the protocol handling mechanism, specifically in how the server processes incoming requests through its native interface. The flaw enables an attacker to manipulate the execution flow of the ClickHouse server process, potentially leading to service disruption or denial of service conditions.
The technical nature of this vulnerability places specific constraints on the attack surface and execution capabilities. The memory redirection is limited to a 256-byte range, indicating that the flaw manifests as a controlled buffer manipulation or pointer arithmetic issue within the server's native protocol parser. This constraint suggests that the vulnerability likely involves an off-by-one error, integer overflow, or similar memory boundary condition that allows partial control over execution flow. The limitation to a 256-byte memory range indicates that while the attack can redirect execution, it cannot directly execute arbitrary code due to the restricted memory access window. This aligns with common software security patterns where memory corruption vulnerabilities are present but constrained by memory layout and access controls. The vulnerability operates at the protocol level rather than at the application level, making it particularly dangerous as it can affect database availability without requiring authentication credentials.
The operational impact of CVE-2024-6873 extends beyond simple service disruption to potentially compromise database availability and integrity within organizations relying on ClickHouse for critical data operations. Organizations utilizing ClickHouse servers without proper network segmentation or authentication measures face heightened risk from this vulnerability, as attackers can exploit it remotely without credentials. The vulnerability affects all currently supported versions of ClickHouse, meaning that organizations running older versions or maintaining custom forks are particularly vulnerable. The lack of confirmed remote code execution capabilities does not diminish the severity of the issue, as denial of service attacks can still cause significant business disruption, data unavailability, and potential financial losses. The vulnerability's impact is particularly concerning in environments where ClickHouse serves as a backend for critical applications, as even brief service interruptions can cascade into broader operational failures. Organizations may experience cascading effects including application downtime, data access restrictions, and potential customer impact.
Mitigation strategies for CVE-2024-6873 should prioritize immediate patching of all supported ClickHouse versions, with particular attention to organizations maintaining custom forks or older versions that have not received the official fix. The fix referenced in the GitHub commit provides a comprehensive solution that addresses the underlying memory handling issue in the native protocol interface. Organizations should implement network segmentation to limit access to ClickHouse native interfaces, particularly when the database is not exposed to untrusted networks. Configuration hardening measures including disabling unnecessary protocols, implementing proper access controls, and monitoring for unusual connection patterns can provide additional defense layers. Security teams should deploy intrusion detection systems capable of identifying suspicious native protocol traffic patterns and establish incident response procedures for handling potential exploitation attempts. Regular vulnerability assessments and security audits of database infrastructure should be conducted to identify similar issues in other components of the database ecosystem. The vulnerability serves as a reminder of the importance of maintaining current security patches and implementing robust network security practices to protect against protocol-level attacks that can compromise service availability. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security fixes across their ClickHouse installations.