CVE-2016-2385 in Kamailio
Summary
by MITRE
Heap-based buffer overflow in the encode_msg function in encode_msg.c in the SEAS module in Kamailio (formerly OpenSER and SER) before 4.3.5 allows remote attackers to cause a denial of service (memory corruption and process crash) or possibly execute arbitrary code via a large SIP packet.
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Analysis
by VulDB Data Team • 10/09/2024
The vulnerability identified as CVE-2016-2385 represents a critical heap-based buffer overflow within the SEAS module of Kamailio, formerly known as OpenSER and SER. This flaw exists in the encode_msg function located in encode_msg.c, making it a significant concern for organizations relying on this SIP server implementation. The vulnerability affects versions prior to 4.3.5 and demonstrates the ongoing challenges in securing telecommunications infrastructure software that processes complex signaling protocols.
The technical nature of this vulnerability stems from improper input validation within the encode_msg function, which fails to adequately check the size of incoming SIP packets before processing them. When a remote attacker sends a specially crafted large SIP packet, the function attempts to allocate memory on the heap to accommodate the data, but due to insufficient boundary checks, the allocation exceeds the intended buffer limits. This heap corruption scenario creates opportunities for both denial of service conditions and potential code execution, as memory corruption can lead to unpredictable program behavior or allow attackers to manipulate execution flow through carefully crafted inputs.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially enable remote code execution on systems running vulnerable versions of Kamailio. The SEAS module is responsible for encoding SIP messages, making it a critical component in SIP communication processing. When exploited, this vulnerability allows attackers to crash the Kamailio process through memory corruption, effectively causing a denial of service that can disrupt VoIP services, SIP trunking, and other telecommunications services relying on the affected software. The potential for arbitrary code execution further elevates the risk, as attackers could gain unauthorized access to systems and potentially escalate privileges.
Mitigation strategies for CVE-2016-2385 primarily focus on upgrading to Kamailio version 4.3.5 or later, which includes patches addressing the heap overflow conditions. Organizations should also implement network-level protections such as rate limiting and SIP message filtering to reduce the impact of potential attacks. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of insufficient boundary checking in memory management operations. From an ATT&CK framework perspective, this vulnerability could be leveraged as part of a broader attack chain involving initial access through network-based exploitation followed by privilege escalation or persistence mechanisms if code execution is achieved. Network segmentation and monitoring of SIP traffic can help detect anomalous packet sizes that may indicate exploitation attempts, while regular security assessments of telecommunications infrastructure remain essential for maintaining robust defenses against such critical vulnerabilities.