SIPp Local Buffer Overflow Vulnerability (CVE-2018-25356)

A local buffer overflow vulnerability, CVE-2018-25356, exists in SIPp version 3.6 and earlier. This flaw stems from insufficient bounds checking when handling command-line arguments. Specifically, the -3pcc, -i, and -log_file parameters are susceptible to buffer overflows due to the use of strcpy in sipp.cpp without proper size validation. A local attacker could leverage this vulnerability to crash the SIPp application or, potentially, execute arbitrary code with the privileges of the user running SIPp. The vulnerability was reported in May 2026. Successful exploitation requires local access to the system running the vulnerable SIPp instance.

Attack Chain

1. The attacker gains local access to a system running a vulnerable version of SIPp (3.6 or earlier).
2. The attacker identifies the SIPp binary location on the system.
3. The attacker constructs a malicious command-line argument string containing an oversized input value for either the -3pcc, -i, or -log_file parameters.
4. The attacker executes the SIPp binary with the crafted command-line arguments, triggering the buffer overflow in sipp.cpp.
5. The strcpy function attempts to copy the oversized input into a fixed-size buffer without checking the buffer boundaries.
6. The buffer overflow overwrites adjacent memory regions, potentially corrupting program data or control flow.
7. The application crashes due to the memory corruption, or the attacker hijacks the program execution flow.
8. If successful, the attacker executes arbitrary code with the privileges of the user running SIPp.

Impact

Successful exploitation of this vulnerability (CVE-2018-25356) could allow a local attacker to crash the SIPp application, leading to a denial-of-service condition. More critically, it could potentially allow the attacker to execute arbitrary code with the privileges of the user running SIPp, potentially leading to privilege escalation and further compromise of the system. Given the nature of SIPp, this could impact VoIP infrastructure testing and simulation environments.

Recommendation

• Upgrade to a version of SIPp that addresses the buffer overflow vulnerability. Check the project’s release page (https://github.com/SIPp/sipp/releases) for patched versions.
• Monitor process creation events for SIPp executions with unusually long command-line arguments, using the Sigma rule provided below.
• Apply host-based intrusion detection system (HIDS) rules to detect attempts to exploit this vulnerability.
• Restrict local access to systems running SIPp to minimize the attack surface.