CVE-2009-1374 in Pidgin
Summary
by MITRE
Buffer overflow in the decrypt_out function in Pidgin (formerly Gaim) before 2.5.6 allows remote attackers to cause a denial of service (application crash) via a QQ packet.
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Analysis
by VulDB Data Team • 09/04/2019
The vulnerability identified as CVE-2009-1374 represents a critical buffer overflow flaw within the Pidgin instant messaging client software. This issue affects versions prior to 2.5.6 and specifically targets the decrypt_out function which handles decryption operations for QQ protocol communications. The vulnerability arises from insufficient input validation and bounds checking within the decryption routine, creating an exploitable condition that can be triggered by maliciously crafted QQ packets transmitted over the network. The QQ protocol implementation in Pidgin was particularly susceptible to this flaw due to its handling of encrypted message payloads and the lack of proper buffer size validation during decryption processes.
The technical exploitation of this vulnerability occurs when a remote attacker sends a specially crafted QQ packet that contains malformed data exceeding the allocated buffer space within the decrypt_out function. This buffer overflow condition causes the application to write beyond the bounds of the allocated memory region, leading to memory corruption that ultimately results in application crash and denial of service. The flaw demonstrates characteristics consistent with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The vulnerability specifically impacts the memory management operations within the protocol handling layer of Pidgin, making it particularly dangerous for users who regularly communicate through QQ protocol connections.
From an operational perspective, this vulnerability presents significant risks to users of Pidgin who rely on QQ protocol support for their instant messaging communications. The remote nature of the attack means that adversaries can exploit this flaw without requiring local access or authentication, making it particularly dangerous in environments where users may receive messages from untrusted sources. The denial of service impact extends beyond simple application crashes, as it can potentially disrupt communication channels and force users to restart their messaging clients repeatedly. The vulnerability affects the overall availability and reliability of the Pidgin client, particularly in enterprise environments where instant messaging systems are critical for business communications. This type of vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks through application-level exploitation.
The mitigation strategy for CVE-2009-1374 involves immediate upgrading to Pidgin version 2.5.6 or later, which contains the necessary patches to address the buffer overflow condition in the decrypt_out function. System administrators should implement comprehensive patch management policies to ensure all affected systems receive updates promptly. Additionally, network monitoring should be enhanced to detect and block suspicious QQ protocol traffic patterns that may indicate exploitation attempts. Organizations should also consider implementing network segmentation to limit exposure of Pidgin clients to untrusted networks and implement proper input validation at network boundaries. The fix implemented in version 2.5.6 includes proper bounds checking and memory allocation validation within the decryption routines, addressing the root cause of the buffer overflow condition that previously allowed attackers to manipulate memory contents through crafted QQ packets.