CVE-2016-10326 in oSIP
Summary
by MITRE
In libosip2 in GNU oSIP 4.1.0, a malformed SIP message can lead to a heap buffer overflow in the osip_body_to_str() function defined in osipparser2/osip_body.c, resulting in a remote DoS.
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Analysis
by VulDB Data Team • 08/30/2020
The vulnerability CVE-2016-10326 represents a critical heap buffer overflow condition within the GNU oSIP library version 4.1.0, specifically affecting the osip_body_to_str() function located in the osipparser2/osip_body.c file. This issue arises from insufficient input validation when processing malformed Session Initiation Protocol messages, creating a remote denial of service scenario that can be exploited by malicious actors to disrupt services. The flaw demonstrates a classic buffer management error where the library fails to properly bounds-check memory allocations during SIP message parsing operations.
The technical implementation of this vulnerability stems from improper handling of malformed SIP body content during the conversion process from parsed message structures to string representations. When the osip_body_to_str() function encounters malformed input data, it attempts to write beyond the allocated heap buffer boundaries, causing memory corruption that can lead to application crashes or system instability. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a fundamental failure in memory management practices within the library's parsing routines. The vulnerability is particularly dangerous because it can be triggered remotely through network-based SIP message transmission, making it accessible to attackers without requiring local system access.
From an operational perspective, this vulnerability poses significant risks to systems relying on GNU oSIP for SIP protocol handling, including VoIP servers, PBX systems, and communication infrastructure components. The remote denial of service capability means that attackers can potentially disrupt critical communication services by sending specially crafted SIP messages that trigger the buffer overflow condition. The impact extends beyond simple service disruption to include potential system instability and resource exhaustion, as the heap corruption can cause cascading failures throughout the application's memory management subsystem. Organizations using affected versions of the library face heightened risk during active SIP communication sessions, particularly in environments where SIP traffic is not properly filtered or validated.
Mitigation strategies for CVE-2016-10326 should prioritize immediate patching of the GNU oSIP library to version 4.1.1 or later, which contains the necessary fixes for the buffer overflow condition. Network administrators should implement SIP message filtering and validation mechanisms to prevent malformed messages from reaching vulnerable systems, utilizing techniques such as rate limiting, content inspection, and protocol compliance checking. The implementation of proper input sanitization and bounds checking within application code that utilizes the library can provide additional defense-in-depth measures, while monitoring systems should be deployed to detect potential exploitation attempts. Organizations should also consider implementing intrusion detection systems capable of identifying suspicious SIP traffic patterns that may indicate exploitation attempts, and regular security assessments should verify that all SIP-related components have been properly updated and validated against known vulnerabilities. This vulnerability exemplifies the importance of robust input validation and memory management practices in network protocol implementations, as outlined in the ATT&CK framework's methodology for identifying and mitigating software vulnerabilities.