CVE-2013-6477 in Pidgin
Summary
by MITRE
Multiple integer signedness errors in libpurple in Pidgin before 2.10.8 allow remote attackers to cause a denial of service (application crash) via a crafted timestamp value in an XMPP message.
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Analysis
by VulDB Data Team • 06/08/2021
The vulnerability identified as CVE-2013-6477 represents a critical security flaw within the libpurple library that powers the Pidgin instant messaging client. This issue stems from multiple integer signedness errors that occur when processing XMPP protocol messages, specifically when handling timestamp values. The vulnerability affects Pidgin versions prior to 2.10.8, making it a significant concern for users who have not updated their installations. The flaw operates at the protocol parsing layer where the application fails to properly validate the signedness of integer values when processing incoming XMPP messages, creating an exploitable condition that can be leveraged by remote attackers.
The technical implementation of this vulnerability involves the manipulation of timestamp values within XMPP messages that are processed by the libpurple library. When these timestamp values contain crafted malicious data, the signedness errors cause the application to interpret these values incorrectly, leading to unexpected behavior in the memory management and processing routines. This misinterpretation results in the application encountering integer overflow conditions or invalid memory access patterns that ultimately cause the application to crash. The vulnerability specifically targets the way the library handles signed and unsigned integer comparisons during timestamp validation, creating a condition where legitimate protocol processing becomes corrupted by malicious input.
From an operational impact perspective, this vulnerability enables remote attackers to execute successful denial of service attacks against Pidgin users without requiring any authentication or privileged access. The attack vector is particularly concerning as it can be executed through standard XMPP message transmission, making it accessible to anyone who can send messages to the target user. The application crash resulting from this vulnerability effectively renders the messaging client unusable for the targeted user, disrupting their communication capabilities and potentially affecting business operations that rely on instant messaging for collaboration. The vulnerability also represents a potential stepping stone for more sophisticated attacks, as the application instability could provide opportunities for further exploitation attempts.
Mitigation strategies for CVE-2013-6477 primarily focus on immediate software updates and protocol-level defenses. The most effective solution involves upgrading to Pidgin version 2.10.8 or later, which contains the necessary patches to address the integer signedness errors in the libpurple library. Organizations should implement automated patch management systems to ensure all affected systems receive updates promptly. Network-level defenses can include implementing XMPP message filtering rules that validate timestamp formats and reject suspicious message content, though this approach may impact legitimate communications. The vulnerability aligns with CWE-191, which describes integer underflow conditions, and represents a specific instance of improper input validation within protocol processing components. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique involving network denial of service, demonstrating how protocol-level flaws can be exploited to create persistent availability issues for targeted systems.
The broader implications of this vulnerability highlight the importance of robust input validation in protocol libraries and the potential for seemingly minor implementation errors to create significant security risks. The issue demonstrates how the interaction between different data types and signedness assumptions in network protocol processing can lead to exploitable conditions that affect widely deployed software components. Security practitioners should consider this vulnerability as a reminder of the critical importance of thorough testing of protocol parsing logic and the need for comprehensive validation of all input data, particularly when dealing with network protocols that may receive untrusted content from multiple sources.