CVE-2010-3443 in Quassel Irc
Summary
by MITRE
ctcphandler.cpp in Quassel before 0.6.3 and 0.7.x before 0.7.1 allows remote attackers to cause a denial of service (unresponsive IRC) via multiple Client-To-Client Protocol (CTCP) requests in a PRIVMSG message.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/10/2022
The vulnerability identified as CVE-2010-3443 affects Quassel, an open-source IRC client that provides a centralized interface for connecting to IRC networks. This issue resides within the ctcphandler.cpp component of the software, which processes CTCP (Client-To-Client Protocol) requests that are commonly used in IRC communications. The vulnerability manifests when multiple CTCP requests are embedded within a single PRIVMSG message, creating a scenario where the application fails to properly handle the malformed input. This specific flaw represents a classic denial of service condition that can render the IRC client unresponsive to legitimate user requests.
The technical implementation of this vulnerability stems from inadequate input validation and processing within Quassel's CTCP handling mechanism. When the application receives a PRIVMSG containing multiple CTCP requests, the ctcphandler.cpp module does not properly parse or limit the number of requests it attempts to process. This leads to a resource exhaustion scenario where the application becomes overwhelmed by the processing demands of multiple concurrent CTCP requests, ultimately causing the client to freeze or become unresponsive. The vulnerability operates at the protocol level, specifically targeting how the client interprets and responds to CTCP messages, making it particularly effective against the IRC communication model. According to CWE standards, this vulnerability maps to CWE-400, which addresses unchecked resource consumption, and CWE-640, which covers weak password recovery mechanisms, though the primary classification focuses on resource exhaustion.
The operational impact of CVE-2010-3443 extends beyond simple service disruption, as it can severely compromise the usability of IRC clients that rely on Quassel's architecture. Attackers can exploit this vulnerability by crafting malicious PRIVMSG messages containing numerous CTCP requests, effectively bringing down IRC sessions and potentially disrupting communication channels for other users. This vulnerability is particularly concerning in environments where IRC clients are used for critical communications or where multiple users interact in shared channels. The attack requires minimal technical expertise to execute, making it a significant risk for any Quassel installation that has not been updated to version 0.6.3 or 0.7.1, depending on the specific version in use. From an ATT&CK framework perspective, this vulnerability aligns with techniques categorized under T1499, which covers network denial of service attacks, and T1566, which involves phishing with malicious attachments or links, though the latter is more indirect in its application.
The mitigation strategy for this vulnerability requires immediate patching of affected Quassel installations to versions 0.6.3 or 0.7.1, which contain the necessary code modifications to properly handle multiple CTCP requests. Organizations should also implement network-level filtering to detect and block malformed PRIVMSG messages containing excessive CTCP requests, though this approach may interfere with legitimate communication patterns. Additionally, system administrators should monitor for unusual CTCP request patterns in IRC traffic and implement logging mechanisms to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and resource management in network applications, particularly those handling protocol-specific communication patterns where malformed data could lead to complete service disruption. Security teams should also consider implementing network segmentation to isolate IRC services and limit the potential impact of successful exploitation attempts.