CVE-2008-2543 in Asterisk-Addons
Summary
by MITRE
The ooh323 channel driver in Asterisk Addons 1.2.x before 1.2.9 and Asterisk-Addons 1.4.x before 1.4.7 creates a remotely accessible TCP port that is intended solely for localhost communication, and interprets some TCP application-data fields as addresses of memory to free, which allows remote attackers to cause a denial of service (daemon crash) via crafted TCP packets.
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Analysis
by VulDB Data Team • 08/01/2021
The vulnerability described in CVE-2008-2543 affects the ooh323 channel driver within Asterisk Addons versions 1.2.x prior to 1.2.9 and 1.4.x prior to 1.4.7. This flaw represents a critical security issue that undermines the integrity of the telephony infrastructure by creating an unintended remote access point. The vulnerability stems from improper network configuration where a TCP port designed exclusively for localhost communication is inadvertently exposed to external networks, creating an attack surface that was never intended to be publicly accessible.
The technical exploitation of this vulnerability occurs through the misinterpretation of TCP application-data fields by the ooh323 channel driver. When legitimate TCP packets are received, the system incorrectly processes certain data fields and interprets them as memory addresses that require deallocation. This misinterpretation leads to the driver attempting to free memory at arbitrary locations, which results in unpredictable behavior and ultimately causes the Asterisk daemon to crash. The flaw essentially allows remote attackers to inject malformed data that triggers improper memory management operations within the telephony application.
From an operational perspective, this vulnerability poses a significant risk to organizations relying on Asterisk-based telephony systems for their communication infrastructure. The denial of service condition created by this vulnerability can result in complete disruption of voice communication services, potentially affecting business operations and emergency communication systems. The remote nature of the attack means that adversaries can exploit this weakness from anywhere on the internet without requiring physical access or prior authentication, making it particularly dangerous for telephony systems that may be exposed to external networks.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-122, which covers buffer overflow vulnerabilities. Additionally, this flaw maps to ATT&CK technique T1499.004, which involves network denial of service attacks through exploitation of system vulnerabilities. The attack vector represents a classic case of improper input validation combined with memory management errors, where the system fails to properly validate incoming TCP data before processing it as memory management instructions.
Organizations should immediately apply the vendor patches released for Asterisk Addons versions 1.2.9 and 1.4.7 to address this vulnerability. Network segmentation should be implemented to ensure that the affected TCP ports remain isolated from external networks, with proper firewall rules restricting access to localhost-only communication. Regular security assessments should include verification of service configurations to ensure that internal ports are not inadvertently exposed to external networks. System monitoring should be enhanced to detect unusual patterns of daemon crashes or restarts that may indicate exploitation attempts. The remediation process should also include reviewing and updating network access controls to prevent similar misconfigurations from occurring in other services within the telephony infrastructure.