CVE-2013-2139 in libsrtp
Summary
by MITRE
Buffer overflow in srtp.c in libsrtp in srtp 1.4.5 and earlier allows remote attackers to cause a denial of service (crash) via vectors related to a length inconsistency in the crypto_policy_set_from_profile_for_rtp and srtp_protect functions.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2013-2139 represents a critical buffer overflow flaw within the Secure Real-time Transport Protocol library implementation known as libsrtp version 1.4.5 and earlier. This issue resides in the srtp.c file and specifically targets the cryptographic policy handling mechanisms that govern how security parameters are configured for real-time communication sessions. The vulnerability manifests when the library processes incoming RTP packets with malformed cryptographic policy profiles, creating conditions where memory boundaries are exceeded during the processing of security parameters. The flaw occurs during the execution of two primary functions: crypto_policy_set_from_profile_for_rtp and srtp_protect, which are responsible for establishing and applying cryptographic policies to protect real-time media streams. Attackers can exploit this vulnerability by crafting specially formatted packets that contain inconsistent length specifications within the cryptographic policy structures, leading to memory corruption when the library attempts to process these malformed inputs.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient checks are performed on input data before memory allocation occurs. The flaw demonstrates characteristics consistent with the ATT&CK technique T1499.004, specifically the use of resource exhaustion attacks through denial of service mechanisms. The buffer overflow occurs because the library fails to validate the length fields within the cryptographic policy structures before attempting to copy or process data into fixed-size buffers. This inconsistency between expected and actual data lengths creates a scenario where attacker-controlled input can overwrite adjacent memory locations, potentially leading to unpredictable behavior including program crashes, memory corruption, or in more severe cases, arbitrary code execution. The vulnerability is particularly concerning in real-time communication systems where libsrtp is commonly deployed, as these environments often process high-volume media streams with minimal input validation.
The operational impact of CVE-2013-2139 extends beyond simple denial of service conditions to potentially compromise entire communication sessions within applications that rely on SRTP for media security. When exploited, the vulnerability can cause applications using libsrtp to crash or become unresponsive, disrupting real-time communication services such as voice over IP, video conferencing, and multimedia streaming platforms. The remote nature of the attack means that adversaries can trigger the vulnerability from outside the network perimeter without requiring local system access or authentication. This makes the vulnerability particularly dangerous in environments where real-time communication systems are exposed to untrusted networks or where attackers can intercept and manipulate RTP traffic streams. The exploitability of this vulnerability is relatively straightforward, requiring only the ability to send crafted packets to a target system running vulnerable libsrtp implementations. Organizations that deploy applications using libsrtp versions prior to 1.4.6 should consider this vulnerability as a high-priority remediation target, especially in environments where real-time media services are critical to business operations or where communication security is paramount.
Mitigation strategies for CVE-2013-2139 should focus on immediate patch deployment to upgrade libsrtp to version 1.4.6 or later, which contains the necessary fixes to validate input lengths before buffer operations. Network administrators should implement monitoring solutions to detect unusual traffic patterns that may indicate exploitation attempts, particularly focusing on RTP traffic with malformed cryptographic policy structures. The implementation of input validation controls at network boundaries, such as firewalls or intrusion detection systems, can help filter out packets that contain suspicious length inconsistencies. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems and applications that utilize vulnerable versions of libsrtp, ensuring that all components in the communication stack are updated to prevent exploitation. Security teams should also consider implementing network segmentation strategies to limit the potential impact of successful exploitation attempts, particularly in environments where multiple real-time communication services are deployed. Regular security updates and patch management processes should be enforced to prevent similar vulnerabilities from being introduced in future versions of the library.