CVE-2007-2294 in Asterisk
Summary
by MITRE
The Manager Interface in Asterisk before 1.2.18 and 1.4.x before 1.4.3 allows remote attackers to cause a denial of service (crash) by using MD5 authentication to authenticate a user that does not have a password defined in manager.conf, resulting in a NULL pointer dereference.
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Analysis
by VulDB Data Team • 07/14/2021
The vulnerability identified as CVE-2007-2294 represents a critical denial of service flaw within the Asterisk telephony system's Manager Interface component. This vulnerability affects versions prior to 1.2.18 and 1.4.3, specifically targeting the authentication mechanism that handles MD5-based user authentication. The flaw manifests when an attacker attempts to authenticate using MD5 credentials for a user account that exists in the system but lacks a defined password entry within the manager.conf configuration file. This particular scenario creates a NULL pointer dereference condition that leads to the complete crash of the Asterisk Manager Interface service, rendering the telephony system unavailable to legitimate users and administrators.
The technical root cause of this vulnerability lies in the improper handling of authentication requests within the Manager Interface module. When the system receives an MD5 authentication attempt for a user account without a corresponding password definition, the authentication routine fails to properly validate the absence of password credentials. This results in the program attempting to dereference a NULL pointer, which causes an immediate crash of the service process. The vulnerability is classified under CWE-476 as a NULL pointer dereference, representing a fundamental programming error where the application fails to check for null values before accessing memory locations. The flaw demonstrates poor input validation and error handling practices that are common in legacy telephony systems where security considerations were not adequately integrated into the development lifecycle.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Asterisk for their communication infrastructure. The remote nature of the attack means that adversaries can exploit this flaw from outside the network perimeter without requiring any special privileges or credentials, making it particularly dangerous for systems exposed to the internet. The denial of service impact is severe as it completely disrupts telephony services, potentially affecting business operations, emergency communication systems, and customer support channels that depend on the Asterisk platform. The vulnerability also provides an entry point for more sophisticated attacks, as the crash can be used to gather information about the system configuration or to establish a baseline for further exploitation attempts. According to ATT&CK framework category T1499, this vulnerability enables adversaries to perform disruption of services, which can serve as a precursor to more advanced attack vectors targeting the broader network infrastructure.
Mitigation strategies for CVE-2007-2294 primarily focus on immediate system updates and configuration hardening. Organizations should upgrade to Asterisk versions 1.2.18 or 1.4.3 and later, which contain the necessary patches to address the NULL pointer dereference issue. System administrators should also implement proper user account management practices, ensuring that all users defined in the manager.conf file have appropriate password entries configured. Network-level protections such as firewall rules can be implemented to restrict access to the Manager Interface to trusted IP addresses only, reducing the attack surface. Additionally, monitoring systems should be configured to detect unusual authentication patterns and service disruptions that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of proper input validation and error handling in telephony applications, particularly those handling remote authentication requests. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious authentication attempts targeting the Manager Interface component. Regular security audits of telephony systems and comprehensive patch management processes are essential to prevent similar vulnerabilities from being exploited in production environments.