CVE-2012-1178 in Pidgin
Summary
by MITRE
The msn_oim_report_to_user function in oim.c in the MSN protocol plugin in libpurple in Pidgin before 2.10.2 allows remote servers to cause a denial of service (application crash) via an OIM message that lacks UTF-8 encoding.
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Analysis
by VulDB Data Team • 11/30/2021
The vulnerability identified as CVE-2012-1178 represents a critical denial of service flaw within the MSN protocol implementation of Pidgin messaging client. This issue resides in the msn_oim_report_to_user function located in the oim.c file of libpurple, which serves as the core library for instant messaging protocols in Pidgin. The vulnerability specifically targets the handling of Outgoing Instant Messages within the MSN protocol plugin, creating a scenario where remote malicious servers can exploit the application's failure to properly validate UTF-8 encoding in incoming OIM messages. This flaw falls under the CWE-129 weakness category, which encompasses issues related to improper validation of input boundaries and encoding handling in network protocols. The vulnerability demonstrates a classic buffer over-read condition where the application attempts to process malformed UTF-8 sequences without adequate sanitization, leading to memory corruption and subsequent application crash.
The operational impact of this vulnerability extends beyond simple service disruption as it enables remote attackers to systematically crash Pidgin clients through crafted OIM messages. When a malicious MSN server sends an OIM message lacking proper UTF-8 encoding, the msn_oim_report_to_user function fails to properly handle the malformed input, resulting in unpredictable application behavior and eventual termination. This vulnerability is particularly concerning within the ATT&CK framework as it maps to the T1499.004 technique for Network Denial of Service, where adversaries exploit application-level flaws to render services unavailable. The flaw affects all Pidgin versions prior to 2.10.2, making it a widespread issue across numerous deployments that rely on the MSN protocol for communication. The vulnerability's exploitation requires minimal network access and can be executed by any remote MSN server, making it highly accessible to threat actors. The crash occurs during message processing rather than during authentication or connection phases, meaning that legitimate users could be disrupted even while maintaining valid sessions with other servers.
Mitigation strategies for CVE-2012-1178 primarily focus on immediate software updates to Pidgin version 2.10.2 or later, which contains the necessary patches to properly validate UTF-8 encoding in incoming OIM messages. System administrators should prioritize patching all affected Pidgin installations across their network infrastructure, particularly in environments where MSN protocol usage is prevalent. Additional defensive measures include implementing network-level filtering to block suspicious MSN protocol traffic, though this approach is less effective as the vulnerability can be exploited through legitimate MSN server interactions. The fix implemented in the patched version addresses the root cause by introducing proper UTF-8 validation checks within the msn_oim_report_to_user function, ensuring that malformed encoding sequences are either properly handled or rejected before they can cause memory corruption. Organizations should also consider monitoring for unusual application crash patterns in their messaging infrastructure, as this vulnerability could serve as an indicator of broader network compromise attempts. The vulnerability's classification as a denial of service issue underscores the importance of maintaining up-to-date security patches and implementing robust application monitoring to detect and respond to such exploits effectively.