CVE-2008-1333 in Asterisk
Summary
by MITRE
Format string vulnerability in Asterisk Open Source 1.6.x before 1.6.0-beta6 might allow remote attackers to execute arbitrary code via logging messages that are not properly handled by (1) the ast_verbose logging API call, or (2) the astman_append function.
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Analysis
by VulDB Data Team • 07/31/2021
The vulnerability described in CVE-2008-1333 represents a critical format string flaw within the Asterisk Open Source telephony platform version 1.6.x prior to beta6 release. This security weakness specifically affects the logging mechanisms of the system and can be exploited by remote attackers to execute arbitrary code on affected systems. The vulnerability stems from improper handling of user-supplied input within the ast_verbose logging API call and the astman_append function, which are fundamental components for logging operations in the Asterisk telephony environment.
Format string vulnerabilities occur when a program uses user input directly in formatting functions without proper validation or sanitization, allowing attackers to manipulate the format string itself rather than just the data being formatted. In the context of Asterisk, this flaw manifests when the system processes logging messages through the affected API calls, where attacker-controlled input can be interpreted as format specifiers. The CWE-134 classification specifically addresses this vulnerability type, where a program uses a format string provided by an attacker, potentially leading to information disclosure, application crashes, or code execution. This vulnerability directly maps to the ATT&CK technique T1059.007 for command and script injection, as successful exploitation could enable remote code execution through manipulated logging operations.
The operational impact of this vulnerability is severe for organizations relying on Asterisk for voice communication services, as it provides a remote code execution vector that could compromise the entire telephony infrastructure. Attackers could leverage this flaw to gain unauthorized access to systems, potentially leading to complete system compromise, data exfiltration, or disruption of critical communication services. The vulnerability affects the core logging functionality that is integral to Asterisk's operation, meaning that any system utilizing these API calls for verbose logging or management operations would be susceptible to exploitation. The remote nature of the attack means that an attacker does not require physical access or prior authentication to exploit this vulnerability, making it particularly dangerous in networked environments where Asterisk servers are exposed to external traffic.
Mitigation strategies for CVE-2008-1333 primarily involve immediate patching of the Asterisk Open Source software to version 1.6.0-beta6 or later, which contains the necessary fixes for the format string vulnerabilities in both ast_verbose and astman_append functions. Organizations should also implement network segmentation to limit exposure of Asterisk servers to untrusted networks and establish proper input validation for all logging operations. Additional defensive measures include monitoring for anomalous logging activity that might indicate exploitation attempts and implementing intrusion detection systems to identify potential attack patterns. The vulnerability highlights the importance of proper input sanitization in all user-facing API functions and demonstrates how seemingly routine logging operations can become critical security attack vectors when not properly secured against format string manipulation.