CVE-2017-17664 in Asterisk
Summary
by MITRE
A Remote Crash issue was discovered in Asterisk Open Source 13.x before 13.18.4, 14.x before 14.7.4, and 15.x before 15.1.4 and Certified Asterisk before 13.13-cert9. Certain compound RTCP packets cause a crash in the RTCP Stack.
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Analysis
by VulDB Data Team • 01/18/2023
The vulnerability identified as CVE-2017-17664 represents a critical remote crash issue affecting Asterisk Open Source versions prior to specific patch releases. This vulnerability resides within the Real-time Transport Control Protocol stack of the Asterisk telephony platform, which is widely deployed in enterprise communication systems and VoIP infrastructure. The flaw manifests when the system processes certain compound RTCP packets, leading to an unexpected termination of the Asterisk process and subsequent service disruption. This type of vulnerability directly impacts the availability and reliability of telephony services, potentially causing significant operational downtime for organizations relying on Asterisk for their communication infrastructure.
The technical implementation of this vulnerability stems from insufficient input validation within the RTCP packet processing mechanism. Compound RTCP packets contain multiple RTCP reports that are processed sequentially by the Asterisk stack, and the vulnerability occurs when malformed or specially crafted compound packets are received. The flaw specifically affects the handling of RTCP header structures and packet boundaries, causing memory corruption or pointer dereference issues that result in immediate process termination. This represents a classic buffer over-read condition that can be exploited remotely without authentication, making it particularly dangerous for publicly accessible VoIP systems. The vulnerability aligns with CWE-125: Out-of-bounds Read, which describes situations where a program reads data past the end of a valid buffer, and may also relate to CWE-20: Improper Input Validation, highlighting the inadequate sanitization of incoming network packets.
The operational impact of CVE-2017-17664 extends beyond simple service disruption, as it can lead to complete communication system failure across affected organizations. When exploited, this vulnerability can cause cascading effects in large enterprise environments where Asterisk serves as a core component of unified communications infrastructure. Network administrators may experience unexpected downtime, call failures, and potential security incidents as attackers leverage this vulnerability to disrupt business operations. The remote nature of the exploit means that attackers can target systems from outside the network perimeter, making traditional network segmentation measures insufficient for protection. Organizations using certified Asterisk versions are also at risk, indicating that the vulnerability affects both community and commercial distributions of the platform.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected Asterisk installations to versions 13.18.4, 14.7.4, 15.1.4, or the certified Asterisk 13.13-cert9 release. Network administrators should implement defensive measures including packet filtering rules that can identify and block malformed RTCP traffic, though this approach may not be comprehensive as the vulnerability can be triggered by legitimate-looking packets. The ATT&CK framework categorizes this vulnerability under T1499.004: Endpoint Denial of Service, which describes techniques that target endpoint systems to make them unavailable to users. Organizations should also consider implementing intrusion detection systems that can monitor for unusual RTCP packet patterns and establish incident response procedures to quickly address exploitation attempts. Additionally, regular vulnerability assessments and network monitoring should be conducted to identify systems that may have been compromised or remain unpatched, as the vulnerability can potentially be used as a stepping stone for more sophisticated attacks within the network infrastructure.