A critical buffer overflow vulnerability in SIPp versions up to 3.7.7 allows unauthenticated remote attackers to cause a denial of service by crashing the application.

The application utilizes a static buffer within the get_peer_tag function to process SIP To headers, which fails to perform adequate bounds checking on tag parameters. Unauthenticated remote attackers can exploit this by sending SIP messages containing tag parameters exceeding 2049 bytes, resulting in a buffer overflow and subsequent process termination.

Successful exploitation of this vulnerability results in a denial of service, rendering the SIPp testing tool unavailable. Given the CVSS score of 7.5, this high severity flaw poses a significant risk to development and quality assurance environments where SIPp is critical for traffic generation and protocol testing. System downtime caused by this crash can disrupt testing cycles and delay deployment pipelines.

Immediate Action: Upgrade to the latest version of SIPp where this buffer overflow is addressed, as identified in the vendor repository.

Proactive Monitoring: Monitor system logs for repeated process crashes or anomalous SIP traffic patterns originating from unexpected sources.

Compensating Controls: Implement network-level filtering or a Web Application Firewall (WAF) configured to inspect and block SIP traffic containing excessively large header parameters.

Public Exploit Available: Unknown

This vulnerability represents a significant stability risk for environments relying on SIPp. Organizations should prioritize updating their software to the latest patched release to prevent potential denial of service attacks. If an immediate update is not feasible, restrict access to the SIPp service to trusted networks to minimize the attack surface.