CVE-2016-7550 in Asterisk
Summary
by MITRE
asterisk 13.10.0 is affected by: denial of service issues in asterisk. The impact is: cause a denial of service (remote).
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Analysis
by VulDB Data Team • 09/24/2023
The vulnerability identified as CVE-2016-7550 affects the Asterisk open source telephony platform version 13.10.0 and represents a significant security flaw that enables remote attackers to execute denial of service attacks against affected systems. This vulnerability specifically targets the signaling processing components within Asterisk, creating conditions where malicious actors can disrupt normal telephony operations without requiring authentication or elevated privileges. The issue stems from improper handling of certain protocol messages and connection states that can lead to system instability and complete service interruption.
The technical root cause of this vulnerability lies in the Asterisk signaling stack where insufficient input validation and state management controls allow crafted malicious packets to trigger unexpected behavior in the telephony engine. When processing specific SIP (Session Initiation Protocol) or IAX2 (Inter-Asterisk eXchange version 2) messages, the system fails to properly validate message parameters and connection states, leading to memory corruption or thread exhaustion conditions. This flaw operates at the protocol level where legitimate telephony traffic can be manipulated to cause the application to enter an inconsistent state, ultimately resulting in process termination or system unresponsiveness. The vulnerability is particularly concerning as it affects core telephony functionality and can be exploited remotely over network connections.
The operational impact of CVE-2016-7550 extends beyond simple service disruption to potentially compromise entire telephony infrastructures that rely on Asterisk for voice communication services. Organizations utilizing Asterisk for business phone systems, call centers, or unified communications platforms face significant risk of service interruptions that can affect critical business operations. The remote exploitation capability means that attackers can target systems from external networks without requiring physical access or local credentials, making this vulnerability particularly dangerous for organizations with exposed telephony services. Network availability is severely compromised as the denial of service can persist until manual system intervention occurs, potentially requiring complete service restarts or system reboots to restore normal operations.
Security professionals should consider this vulnerability in the context of the Common Weakness Enumeration framework where it maps to CWE-400, representing an unchecked resource consumption weakness. The attack surface aligns with ATT&CK technique T1499.004 which describes network denial of service attacks. Organizations should implement immediate mitigations including network segmentation to limit access to telephony services, deploying intrusion detection systems to monitor for suspicious signaling patterns, and applying the vendor-provided patches as soon as possible. The vulnerability also highlights the importance of input validation and proper error handling in telephony applications, as well as the need for comprehensive testing of protocol implementations against malformed inputs. Regular security assessments and monitoring of telephony infrastructure should be conducted to identify similar weaknesses that could enable exploitation of similar remote denial of service conditions.