CVE-2012-2214 in Pidgin
Summary
by MITRE
proxy.c in libpurple in Pidgin before 2.10.4 does not properly handle canceled SOCKS5 connection attempts, which allows user-assisted remote authenticated users to cause a denial of service (application crash) via a sequence of XMPP file-transfer requests.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2012-2214 resides within the libpurple library component of Pidgin messaging client, specifically in the proxy.c file that manages SOCKS5 proxy connections. This flaw represents a classic buffer management issue that occurs during the handling of canceled SOCKS5 connection attempts, creating a condition where the application fails to properly validate or process connection state changes. The vulnerability is particularly concerning because it affects the core networking functionality of Pidgin, which is widely used across multiple operating systems and platforms for instant messaging and chat communications.
The technical implementation of this vulnerability stems from improper state handling within the SOCKS5 proxy connection management code. When a SOCKS5 connection attempt is canceled by the user or network conditions, the proxy.c module fails to properly clean up or validate the connection state before proceeding with subsequent operations. This improper handling creates a scenario where malicious or cooperating remote authenticated users can craft specific XMPP file-transfer requests that trigger the cancellation sequence in a manner designed to exploit the application's lack of proper state validation. The flaw essentially allows an attacker to manipulate the connection state machine in a way that leads to memory corruption or invalid pointer dereferences.
The operational impact of this vulnerability manifests as a denial of service condition that results in application crashes, effectively rendering the Pidgin client unusable for the affected user. This type of vulnerability can be particularly disruptive in enterprise environments where Pidgin serves as a primary communication tool, as it can be exploited by authenticated users to create persistent service interruptions. The user-assisted nature of the attack means that the victim must be tricked into accepting or initiating a specific sequence of file transfer requests, but the actual exploitation requires minimal technical expertise beyond crafting the appropriate XMPP protocol messages. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a specific implementation flaw in connection state management.
The attack vector for this vulnerability operates through the XMPP protocol's file transfer mechanisms, where authenticated users can initiate file transfer requests that trigger the problematic SOCKS5 connection handling code path. The vulnerability requires that the attacker have valid credentials to access the target user's account, making it a privilege escalation or lateral movement tool rather than a direct remote code execution vulnerability. However, the impact remains significant as it can be used to create persistent service disruption, particularly in environments where multiple users rely on the same communication infrastructure. This vulnerability also relates to ATT&CK technique T1489, which describes creating or deploying malicious code to deny access to systems, and T1071, which covers application layer protocol usage for command and control communications.
Mitigation strategies for CVE-2012-2214 primarily involve updating to Pidgin version 2.10.4 or later, which contains the necessary code fixes to properly handle canceled SOCKS5 connection attempts. System administrators should also implement network monitoring to detect unusual XMPP file transfer patterns that might indicate exploitation attempts. Additional defensive measures include configuring firewalls to limit XMPP traffic between users and implementing proper access controls for file transfer functionality. The vulnerability demonstrates the importance of proper state machine implementation in networked applications and highlights the need for comprehensive testing of connection cancellation scenarios. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious XMPP protocol sequences that may indicate attempts to exploit similar connection handling flaws in other messaging applications.