CVE-2013-6486 in Pidgin
Summary
by MITRE
gtkutils.c in Pidgin before 2.10.8 on Windows allows user-assisted remote attackers to execute arbitrary programs via a message containing a file: URL that is improperly handled during construction of an explorer.exe command. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3185.
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Analysis
by VulDB Data Team • 07/31/2019
The vulnerability identified as CVE-2013-6486 represents a critical remote code execution flaw in Pidgin messaging client versions prior to 2.10.8 on Windows platforms. This security issue stems from improper handling of file:// URLs within the gtkutils.c component, specifically during the construction of explorer.exe commands. The vulnerability serves as a continuation of the remediation efforts for CVE-2011-3185, indicating that the initial fix was insufficient to fully address the underlying security concern. Attackers can exploit this weakness by crafting malicious messages containing file:// URLs that, when processed by the vulnerable Pidgin client, trigger unauthorized execution of arbitrary programs on the target system. The flaw exploits the trust relationship between the messaging application and the operating system's file explorer functionality, creating a pathway for malicious code delivery through seemingly innocuous chat messages.
The technical implementation of this vulnerability involves the improper sanitization and validation of file:// URLs within Pidgin's user interface components. When a user receives a message containing a specially crafted file:// URL, the gtkutils.c module attempts to construct an explorer.exe command to handle the URL reference. However, the incomplete fix for CVE-2011-3185 failed to adequately address all potential attack vectors, leaving the system susceptible to command injection. The flaw specifically occurs during the URL parsing and command construction phases, where user-supplied input is directly incorporated into system commands without proper validation or escaping mechanisms. This creates a classic command injection vulnerability that can be exploited to execute arbitrary code with the privileges of the affected user account. The vulnerability manifests through the Windows operating system's file explorer handling of URLs, where malicious file:// references can trigger unintended system behavior.
From an operational perspective, this vulnerability poses significant risks to users of the Pidgin messaging client in enterprise and personal environments. The user-assisted nature of the attack means that victims must actively engage with the malicious message content, typically by clicking on the embedded URL or viewing the message in a context that triggers the vulnerable code path. However, this requirement does not diminish the severity of the threat, as social engineering techniques can easily convince users to interact with malicious content. The potential impact extends beyond simple code execution to include complete system compromise, data theft, and lateral movement within network environments. Organizations relying on Pidgin for communication are particularly vulnerable, as the messaging application often serves as a primary means of internal and external communication, making it an attractive target for adversaries seeking persistent access. The vulnerability affects not only individual users but also corporate networks where Pidgin is deployed as part of standard communication infrastructure.
The remediation strategy for CVE-2013-6486 requires immediate deployment of Pidgin version 2.10.8 or later, which contains the comprehensive fix for the URL handling vulnerability. System administrators should implement mandatory update policies to ensure all affected clients are patched promptly. Additional mitigations include configuring network firewalls to block outbound connections to suspicious domains and implementing email filtering solutions that can detect and quarantine messages containing potentially malicious URLs. Security monitoring should focus on identifying unusual explorer.exe process execution patterns and monitoring for command injection attempts. Organizations should also consider implementing application whitelisting policies that restrict the execution of unauthorized programs, particularly those that might be triggered by file:// URL handling. The vulnerability demonstrates the importance of thorough vulnerability remediation and the potential consequences of incomplete security fixes. According to CWE classification, this vulnerability maps to CWE-78 which addresses improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should conduct regular security assessments to identify similar incomplete fixes in their software inventory and ensure comprehensive vulnerability management practices are in place to prevent such issues from recurring in future security updates.