CVE-2016-10324 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_clrncpy() function defined in osipparser2/osip_port.c.
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Analysis
by VulDB Data Team • 08/30/2020
The vulnerability CVE-2016-10324 represents a critical heap buffer overflow flaw within the libosip2 library component of GNU oSIP version 4.1.0. This issue specifically manifests in the osip_clrncpy() function located in the osipparser2/osip_port.c file, where improper handling of malformed SIP (Session Initiation Protocol) messages creates exploitable conditions that can be leveraged by attackers to compromise system integrity. The vulnerability arises from insufficient input validation and bounds checking mechanisms within the library's parsing routines, which are fundamental components for processing SIP communications in VoIP systems and other real-time communication applications.
The technical implementation of this flaw stems from the osip_clrncpy() function's failure to properly validate the length of input data before performing memory copy operations. When a malformed SIP message is received, the function attempts to copy data into a heap-allocated buffer without adequate bounds verification, leading to a situation where more data is written than the allocated buffer space can accommodate. This classic buffer overflow condition creates opportunities for memory corruption that can be exploited to execute arbitrary code, manipulate program flow, or cause denial of service conditions. The vulnerability is particularly concerning given that SIP protocol implementations are widely deployed in enterprise communication systems, PBX networks, and VoIP infrastructure where reliability and security are paramount.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can be leveraged in various attack scenarios that align with the ATT&CK framework's privilege escalation and execution tactics. An attacker who can inject malformed SIP messages into a vulnerable system can potentially achieve remote code execution, allowing them to gain unauthorized access to network services that rely on GNU oSIP for SIP message processing. This includes but is not limited to VoIP servers, PBX systems, SIP proxies, and communication gateways that form the backbone of enterprise telephony infrastructure. The vulnerability affects systems where the libosip2 library is integrated, making it particularly dangerous in environments where SIP-based communications are prevalent and where attackers might exploit the flaw through network-based attacks targeting SIP endpoints.
Security mitigations for CVE-2016-10324 should focus on immediate library updates and patches provided by the GNU oSIP maintainers, as well as implementing network-level protections that filter malformed SIP traffic before it reaches vulnerable applications. Organizations should also consider input validation layers, memory protection mechanisms such as stack canaries and address space layout randomization, and comprehensive monitoring for unusual SIP message patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions as critical weaknesses in data handling, and represents a clear example of how protocol parsing flaws can create persistent security risks in widely-deployed software libraries. System administrators should prioritize patch management processes to ensure all affected systems are updated promptly, as the window of opportunity for exploitation remains significant given the widespread use of GNU oSIP in communication infrastructure.