CVE-2017-8073 in WeeChat
Summary
by MITRE
WeeChat before 1.7.1 allows a remote crash by sending a filename via DCC to the IRC plugin. This occurs in the irc_ctcp_dcc_filename_without_quotes function during quote removal, with a buffer overflow.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/02/2022
The vulnerability identified as CVE-2017-8073 represents a critical buffer overflow flaw in WeeChat versions prior to 1.7.1 that specifically affects the IRC plugin's handling of DCC file transfers. This vulnerability arises from improper input validation within the irc_ctcp_dcc_filename_without_quotes function, where the software fails to adequately sanitize filename data received through DCC communications. The flaw manifests when a remote attacker sends a malicious filename via DCC to the IRC plugin, triggering a buffer overflow condition that can lead to application instability and potential system compromise.
The technical implementation of this vulnerability demonstrates a classic buffer overflow exploit pattern where insufficient bounds checking occurs during quote removal operations. When WeeChat processes a DCC filename, the irc_ctcp_dcc_filename_without_quotes function attempts to strip quotes from the filename string without verifying that the resulting buffer can accommodate the modified data. This oversight creates a scenario where an attacker can craft a specially formatted filename that exceeds the allocated buffer space, causing memory corruption that may result in arbitrary code execution or denial of service conditions. The vulnerability specifically targets the IRC plugin's CTCP DCC implementation, making it particularly dangerous in environments where users frequently engage in file transfers through IRC channels.
From an operational perspective, this vulnerability presents significant risks to users who maintain WeeChat installations in networked environments where remote attackers may have access to IRC channels. The remote nature of the exploit means that an attacker does not require physical access to the target system or direct network connectivity to the vulnerable application. Instead, they can simply join an IRC channel and send a malicious filename through DCC to trigger the buffer overflow condition. The impact extends beyond simple application crashes, as buffer overflows of this nature can potentially be leveraged for privilege escalation or arbitrary code execution, particularly if the application runs with elevated privileges. This vulnerability directly maps to CWE-121, which addresses stack-based buffer overflow conditions, and represents a clear violation of secure coding practices regarding input validation and memory management.
The attack surface for this vulnerability is particularly concerning given WeeChat's widespread use as an IRC client across various network environments including corporate networks, research institutions, and personal computing environments. Organizations that rely on IRC communications for collaboration or monitoring activities face potential exposure to this vulnerability, especially when users are not properly trained about the risks of accepting DCC file transfers from untrusted sources. The exploit requires minimal technical expertise to execute, making it particularly dangerous in environments where users may unknowingly accept malicious file transfers. Security practitioners should consider this vulnerability in their threat modeling exercises and implement appropriate network segmentation to limit exposure. The recommended mitigation involves upgrading to WeeChat version 1.7.1 or later, which includes proper bounds checking and input validation to prevent the buffer overflow condition from occurring. Additionally, network administrators should consider implementing DCC transfer restrictions or disabling DCC functionality entirely in high-security environments to prevent exploitation opportunities.
This vulnerability demonstrates the importance of proper input validation and memory management in client applications that process untrusted data from network sources. The flaw highlights the need for robust defensive programming practices including bounds checking, input sanitization, and proper error handling in applications that process user-supplied data. Organizations should prioritize patch management for this vulnerability and consider implementing network-based detection measures to identify potential exploitation attempts. The vulnerability also underscores the importance of regular security assessments of client applications that handle network communications, particularly those that process file transfers or other binary data from remote sources. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving remote code execution and privilege escalation, making it a significant concern for organizations implementing comprehensive cybersecurity frameworks.