CVE-2012-2186 in Asterisk
Summary
by MITRE
Incomplete blacklist vulnerability in main/manager.c in Asterisk Open Source 1.8.x before 1.8.15.1 and 10.x before 10.7.1, Certified Asterisk 1.8.11 before 1.8.11-cert6, Asterisk Digiumphones 10.x.x-digiumphones before 10.7.1-digiumphones, and Asterisk Business Edition C.3.x before C.3.7.6 allows remote authenticated users to execute arbitrary commands by leveraging originate privileges and providing an ExternalIVR value in an AMI Originate action.
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Analysis
by VulDB Data Team • 08/15/2024
The vulnerability described in CVE-2012-2186 represents a critical security flaw in Asterisk Open Source and its certified variants, specifically affecting versions prior to the mentioned patches. This issue resides within the main/manager.c component of the Asterisk telephony platform, which serves as the core management interface for system administration and call control operations. The vulnerability stems from an incomplete blacklist implementation that fails to properly validate input parameters, creating a pathway for malicious actors to exploit the system's originate functionality. The affected versions include Asterisk 1.8.x before 1.8.15.1, 10.x before 10.7.1, certified Asterisk 1.8.11 before 1.8.11-cert6, Asterisk Digiumphones 10.x.x-digiumphones before 10.7.1-digiumphones, and Asterisk Business Edition C.3.x before C.3.7.6, indicating a widespread impact across multiple Asterisk product lines and versions.
The technical flaw manifests through the AMI (Asterisk Manager Interface) Originate action, which allows authorized users to initiate outbound calls programmatically. The vulnerability specifically exploits the ExternalIVR parameter within this action, which should have been properly sanitized and validated against a comprehensive blacklist of dangerous characters and command sequences. However, the incomplete blacklist implementation permits certain malicious inputs to bypass validation checks, enabling attackers with originate privileges to inject arbitrary commands into the system. This type of vulnerability falls under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter. The flaw essentially allows privilege escalation from authenticated user access to full system command execution, as the system processes the malicious ExternalIVR value as executable code rather than as a simple parameter.
The operational impact of this vulnerability is severe and far-reaching for organizations relying on Asterisk for their communication infrastructure. Attackers who can authenticate to the Asterisk system with originate privileges can leverage this vulnerability to execute arbitrary commands on the underlying operating system, potentially gaining complete control over the telephony server. This could lead to unauthorized access to sensitive communication data, disruption of critical business communications, data exfiltration, and even lateral movement within the network infrastructure. The vulnerability particularly affects enterprises using Asterisk for PBX systems, VoIP communications, and call center operations, where the compromise of the telephony infrastructure can have cascading effects on business continuity and regulatory compliance. Organizations using certified Asterisk versions or specialized Asterisk distributions like Digiumphones and Business Edition are equally at risk, highlighting the widespread nature of this security gap.
Mitigation strategies for CVE-2012-2186 should focus on immediate patch application to the affected versions, as this represents the most effective solution to address the root cause of the vulnerability. System administrators should prioritize upgrading to the patched versions mentioned in the CVE description, ensuring that all variants including certified Asterisk, Digiumphones, and Business Edition are updated accordingly. Additionally, organizations should implement network segmentation to limit access to the Asterisk Manager Interface, restrict originate privileges to only essential administrative users, and deploy comprehensive monitoring solutions to detect anomalous command execution patterns. The implementation of proper input validation and parameter sanitization should be enforced across all AMI actions, with a focus on creating robust blacklists that account for all potentially dangerous characters and command sequences. Security teams should also consider implementing intrusion detection systems specifically tuned to identify exploitation attempts targeting the AMI interface and monitor for unusual originate operations that could indicate an active attack. This vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the necessity of robust input validation mechanisms in telephony and communication platforms, as the consequences of such flaws extend beyond simple data exposure to full system compromise.