CVE-2011-1174 in Asterisk
Summary
by MITRE
manager.c in Asterisk Open Source 1.6.1.x before 1.6.1.24, 1.6.2.x before 1.6.2.17.2, and 1.8.x before 1.8.3.2 allows remote attackers to cause a denial of service (CPU and memory consumption) via a series of manager sessions involving invalid data.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2011-1174 represents a critical denial of service weakness within the Asterisk Open Source telephony platform that affects multiple version streams including 1.6.1.x prior to 1.6.1.24, 1.6.2.x prior to 1.6.2.17.2, and 1.8.x prior to 1.8.3.2. This flaw resides in the manager.c component which handles remote management connections to the Asterisk system through its Manager API interface. The vulnerability specifically targets the handling of manager sessions and demonstrates how improper validation of incoming data can lead to resource exhaustion attacks that can bring down the entire telephony infrastructure.
The technical implementation of this vulnerability exploits the lack of proper input validation within the manager session handling mechanism. When remote attackers establish manager sessions and submit malformed or invalid data sequences, the system fails to properly sanitize these inputs before processing them within the manager.c module. This deficiency creates a condition where the system continues to consume increasing amounts of CPU cycles and memory resources as it attempts to process these invalid data sequences. The flaw operates through a combination of memory allocation patterns and processing loops that become increasingly inefficient when encountering malformed input, leading to progressive resource consumption that can eventually overwhelm the system's capabilities.
The operational impact of CVE-2011-1174 extends beyond simple service disruption to potentially compromise the entire telephony infrastructure. Attackers can maintain persistent resource consumption by establishing multiple manager sessions with invalid data, causing the Asterisk system to continuously allocate memory and process CPU cycles without proper termination of these malicious sessions. This vulnerability directly maps to CWE-400, which describes "Uncontrolled Resource Consumption" and aligns with ATT&CK technique T1499.1, "Network Denial of Service" as it enables remote attackers to exhaust system resources through network-based attacks. The vulnerability's remote exploitability means that attackers do not require local access or authentication credentials to initiate the attack, making it particularly dangerous for publicly accessible telephony systems.
Mitigation strategies for this vulnerability require immediate patching of affected Asterisk versions to the corrected releases that address the input validation issues within manager.c. Organizations should implement network segmentation to restrict access to the Manager API ports, typically TCP 5038, to only trusted management systems and administrators. Additionally, implementing connection rate limiting and session monitoring can help detect and prevent the exploitation of this vulnerability by identifying abnormal patterns of manager session establishment with invalid data. The remediation approach should also include monitoring for unusual CPU and memory consumption patterns that may indicate exploitation attempts. Security teams should also consider implementing intrusion detection systems that can identify malformed manager API requests and automatically block suspicious traffic patterns. Organizations with legacy systems that cannot be immediately patched should implement additional network controls to restrict Manager API access and establish strict authentication requirements for any legitimate management access to prevent unauthorized exploitation of this vulnerability.