CVE-2005-4681 in mIRC
Summary
by MITRE
** DISPUTED ** Buffer overflow in mIRC 5.91, 6.03, 6.12, and 6.16 allows local users to execute arbitrary code via a long string that is entered after reaching the DCC Get Folder Dialog. NOTE: this issue has been disputed by the vendor, saying "as far as I can tell, this is neither an exploit nor a vulnerability. The above report describes a local bug in mIRC." It could be that this is only exploitable by the user of the application, and thus would not cross privilege boundaries unless under an otherwise restrictive environment such as a kiosk.
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability identified as CVE-2005-4681 pertains to a buffer overflow condition discovered in multiple versions of the mIRC instant messaging client including versions 5.91, 6.03, 6.12, and 6.16. This flaw manifests when a local user interacts with the DCC Get Folder Dialog functionality within the application, specifically when entering a string that exceeds the allocated buffer space. The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The buffer overflow occurs during the processing of user input within the DCC (Direct Client-to-Client) file transfer mechanism, a feature commonly used for sharing files between mIRC users in real-time communication sessions.
From an operational perspective, this vulnerability presents a significant risk to local system integrity as it allows for arbitrary code execution within the context of the mIRC process. The attack vector requires local user interaction, meaning that exploitation would typically occur when a user intentionally or unintentionally triggers the vulnerable code path by entering excessive input into the DCC Get Folder Dialog. This characteristic places the vulnerability in the ATT&CK framework under T1059.007 for Command and Scripting Interpreter and potentially T1068 for Exploitation for Privilege Escalation, though the latter would depend on the privilege level of the mIRC process. The local nature of the exploit means that it would not typically be used for remote attacks against systems, but rather represents an escalation risk within a compromised local environment.
The vendor's disputed stance on this vulnerability suggests that the reported issue may not constitute a traditional security vulnerability since it requires local user interaction and operates within the same privilege context as the application itself. This assessment aligns with the principle that local buffer overflows that do not cross privilege boundaries typically do not meet the criteria for high-severity security vulnerabilities in traditional threat models. However, the vulnerability remains relevant in specific environments such as kiosk systems or restricted user environments where local privilege escalation could lead to broader system compromise. The vulnerability's classification as local in nature means that while it may not pose a direct threat to network security, it could be leveraged as part of a multi-stage attack in environments where local system access is already achieved. Organizations should consider this vulnerability as part of their overall security posture assessment, particularly in environments where mIRC is deployed with elevated privileges or in controlled access scenarios where local compromise could lead to further system infiltration. The issue highlights the importance of input validation and bounds checking in client-side applications, especially those handling user-provided data in file transfer and communication contexts, as such vulnerabilities can serve as entry points for more sophisticated attacks when combined with other exploitation techniques or in specific environmental conditions.