CVE-2017-14727 in WeeChat
Summary
by MITRE
logger.c in the logger plugin in WeeChat before 1.9.1 allows a crash via strftime date/time specifiers, because a buffer is not initialized.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-14727 affects the logger plugin in WeeChat versions prior to 1.9.1, representing a classic buffer management flaw that can lead to denial of service conditions. This issue resides within the logger.c file where the logger plugin processes date and time formatting operations using strftime function calls. The core problem emerges from insufficient buffer initialization during the processing of time format specifiers, creating a scenario where malformed or unexpected input can cause the application to crash.
The technical implementation of this vulnerability stems from the improper handling of memory allocation within the logger plugin's date formatting functionality. When WeeChat processes log entries that contain specific strftime date/time format specifiers, the underlying buffer that stores the formatted time string fails to be properly initialized before being populated with data. This uninitialized buffer state creates a memory access violation when the application attempts to write formatted time data, resulting in an abrupt termination of the WeeChat process. The flaw demonstrates characteristics consistent with CWE-457, which addresses the use of uninitialized variables, and more specifically aligns with CWE-125, concerning the reading of memory outside the bounds of a valid buffer.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited by malicious actors to perform denial of service attacks against WeeChat instances. Attackers can craft specially formatted log entries or manipulate time format specifications to trigger the buffer overflow condition, causing the messaging client to crash and potentially lose active connections or pending messages. This vulnerability particularly affects systems where WeeChat is used as a persistent logging service or where automated log processing occurs, as the crash can occur during routine operations without user intervention. The exploitability is relatively straightforward since it requires only the ability to influence log entry content or time formatting parameters, making it accessible to attackers with minimal privileges within the system.
Mitigation strategies for CVE-2017-14727 involve immediate patching of WeeChat installations to version 1.9.1 or later, where the buffer initialization issue has been corrected. System administrators should also implement monitoring for unusual crash patterns in WeeChat processes, particularly around logging activities, and consider implementing input validation for time format specifiers used in logging configurations. The fix implemented in the patched version addresses the root cause by ensuring proper buffer initialization before strftime operations, preventing the memory access violations that previously occurred. Organizations using WeeChat in production environments should conduct thorough testing of the updated software to ensure compatibility with existing logging configurations and workflows, while also reviewing their overall security posture to prevent similar buffer management issues in other components of their infrastructure. This vulnerability serves as a reminder of the critical importance of proper memory management practices and the potential for seemingly minor initialization flaws to result in significant service availability impacts.