CVE-2014-4047 in Asterisk
Summary
by MITRE
Asterisk Open Source 1.8.x before 1.8.28.1, 11.x before 11.10.1, and 12.x before 12.3.1 and Certified Asterisk 1.8.15 before 1.8.15-cert6 and 11.6 before 11.6-cert3 allows remote attackers to cause a denial of service (connection consumption) via a large number of (1) inactive or (2) incomplete HTTP connections.
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Analysis
by VulDB Data Team • 06/22/2021
The vulnerability identified as CVE-2014-4047 represents a significant denial of service weakness in Asterisk Open Source and Certified Asterisk implementations. This flaw affects multiple version streams including 1.8.x before 1.8.28.1, 11.x before 11.10.1, 12.x before 12.3.1, and specific certified versions with corresponding patch levels. The vulnerability manifests when the system encounters a large volume of inactive or incomplete HTTP connections, creating a scenario where legitimate service availability is compromised through resource exhaustion.
The technical root cause of this vulnerability lies in the insufficient handling of HTTP connection states within the Asterisk application server. When remote attackers establish numerous HTTP connections that remain inactive or become incomplete, the system fails to properly manage these connection resources. This improper resource management leads to connection consumption that gradually depletes available system resources, ultimately causing the service to become unresponsive or crash entirely. The flaw operates at the protocol handling layer where HTTP connection lifecycle management lacks adequate timeout mechanisms and resource cleanup procedures.
The operational impact of CVE-2014-4047 is severe and directly affects the availability of critical communication services. Organizations relying on Asterisk for VoIP infrastructure, web services, or unified communications face potential disruption of their services when subjected to this attack vector. The vulnerability enables attackers to consume system resources without requiring authentication or specialized privileges, making it particularly dangerous for publicly accessible Asterisk installations. Network administrators may observe gradual performance degradation followed by complete service unavailability, affecting both internal and external communication systems that depend on the affected Asterisk instances.
This vulnerability maps to CWE-400, which specifically addresses Uncontrolled Resource Consumption, and aligns with ATT&CK technique T1499.004 for Network Denial of Service. The attack pattern follows a resource exhaustion methodology where attackers leverage the system's inadequate connection handling to consume available connections. Security practitioners should note that the vulnerability affects multiple major version streams, indicating a fundamental flaw in the HTTP connection management architecture that required patches across different release branches.
Mitigation strategies for CVE-2014-4047 primarily involve applying the vendor-supplied patches and updates to all affected Asterisk installations. System administrators should immediately upgrade to the patched versions including 1.8.28.1, 11.10.1, 12.3.1, and their respective certified releases. Additionally, implementing connection timeout configurations and resource limits can provide defense-in-depth measures. Network-level protections such as connection rate limiting and firewall rules that restrict HTTP connection attempts can help reduce the impact of such attacks. Monitoring systems should be configured to detect unusual connection patterns and alert administrators to potential exploitation attempts. Regular security assessments and vulnerability scanning should include verification of patched status to ensure complete remediation across all Asterisk installations within the organization's infrastructure.