CVE-2012-5854 in WeeChat
Summary
by MITRE
Heap-based buffer overflow in WeeChat 0.3.6 through 0.3.9 allows remote attackers to cause a denial of service (crash or hang) and possibly execute arbitrary code via crafted IRC colors that are not properly decoded.
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability identified as CVE-2012-5854 represents a critical heap-based buffer overflow affecting WeeChat versions 0.3.6 through 0.3.9, specifically within the IRC protocol handling component. This flaw resides in the software's inability to properly decode and validate crafted IRC color codes, which are commonly used in internet relay chat communications to format text with different colors and styles. The vulnerability operates at the intersection of input validation and memory management, creating a scenario where malformed data can corrupt heap memory structures during processing. The affected WeeChat versions represent a significant portion of the software's user base, making this vulnerability particularly dangerous as it could impact a large number of users simultaneously.
The technical implementation of this vulnerability stems from improper handling of escape sequences and color formatting codes within IRC messages. When WeeChat processes incoming IRC messages containing specially crafted color codes, the software fails to validate the length and structure of these sequences before attempting to store them in allocated heap memory buffers. This insufficient validation allows attackers to craft input data that exceeds the allocated buffer boundaries, causing memory corruption that can result in program termination or potentially arbitrary code execution. The vulnerability manifests as a heap-based buffer overflow because the affected memory allocation occurs on the heap rather than the stack, making exploitation more complex but still feasible for determined attackers. The issue directly maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory locations.
The operational impact of CVE-2012-5854 extends beyond simple denial of service, as it presents potential for remote code execution in vulnerable configurations. Attackers can leverage this vulnerability by sending maliciously crafted IRC messages containing malformed color codes to WeeChat clients, causing the application to crash or potentially execute arbitrary code with the privileges of the affected user. This creates a significant risk for users who participate in public or untrusted IRC channels, as the vulnerability can be exploited through simple message transmission without requiring additional authentication or privileges. The vulnerability affects both the stability and security posture of WeeChat installations, as it can be triggered remotely without user interaction beyond normal IRC communication. This makes it particularly dangerous in environments where users may encounter untrusted content or where the software operates with elevated privileges, potentially allowing attackers to escalate their access level within the system.
Mitigation strategies for CVE-2012-5854 focus on immediate software updates and input validation improvements. The most effective remediation involves upgrading to WeeChat versions 0.3.10 or later, where the buffer overflow vulnerability has been addressed through proper input validation and bounds checking mechanisms. Organizations should implement network-level filtering to restrict potentially malicious IRC traffic, particularly when users connect to public IRC networks where untrusted content is common. Additionally, administrators should consider implementing runtime protections such as stack canaries and address space layout randomization to make exploitation more difficult. The vulnerability demonstrates the importance of proper input sanitization and memory management practices, aligning with ATT&CK technique T1059.007 for command and scripting interpreter usage, as attackers may attempt to exploit the vulnerability to execute malicious code. Security monitoring should include detection of unusual memory allocation patterns and potential buffer overflow indicators, with particular attention to IRC protocol handling within chat applications. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other software components that may be susceptible to similar memory corruption vulnerabilities.