CVE-2012-4869 in FreePBX
Summary
by MITRE
The callme_startcall function in recordings/misc/callme_page.php in FreePBX 2.9, 2.10, and earlier allows remote attackers to execute arbitrary commands via the callmenum parameter in a c action.
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Analysis
by VulDB Data Team • 01/13/2025
The vulnerability identified as CVE-2012-4869 represents a critical command injection flaw within the FreePBX telephony system that affects versions 2.9 through 2.10. This issue resides in the callme_startcall function located within the recordings/misc/callme_page.php file, creating a pathway for remote attackers to execute arbitrary system commands through malicious manipulation of the callmenum parameter when the c action is invoked. The flaw stems from inadequate input validation and sanitization practices within the application's codebase, allowing attackers to inject malicious commands that are subsequently executed with the privileges of the web application. This vulnerability is categorized under CWE-77 as a command injection weakness, which is a well-documented and dangerous class of vulnerability that enables attackers to execute arbitrary code on the affected system.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with complete control over the affected FreePBX system. Successful exploitation could result in unauthorized access to the underlying operating system, enabling attackers to install malware, steal sensitive data, modify system configurations, or establish persistent backdoors. The vulnerability affects the core telephony infrastructure of organizations that rely on FreePBX for their communication systems, potentially compromising not only the system itself but also the broader network ecosystem. Attackers could leverage this flaw to escalate privileges, access voicemail systems, manipulate call routing, or even use the compromised system as a pivot point to attack other networked devices. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access or prior authentication to the system.
The technical exploitation of this vulnerability follows established patterns consistent with command injection attacks as documented in the MITRE ATT&CK framework under technique T1059.001 for command and script interpreters, and T1078 for valid accounts, as attackers can leverage the web application's execution context to run arbitrary commands. The vulnerability demonstrates poor input validation practices where user-supplied data from the callmenum parameter is directly incorporated into system commands without proper sanitization or escaping. This allows attackers to inject command delimiters and additional shell commands that are then executed by the system shell. The attack vector is particularly dangerous because it targets a web-based interface that is often accessible from external networks, making it an attractive target for remote exploitation. Organizations using vulnerable versions of FreePBX are at significant risk of compromise, especially when the system is exposed to untrusted networks or lacks proper network segmentation controls. The remediation approach must include immediate patching of the FreePBX system to the latest available version that addresses this vulnerability, along with implementing network-level controls to restrict access to the affected web interface. Additionally, organizations should conduct thorough security assessments of their telephony infrastructure and implement proper input validation controls throughout their applications to prevent similar vulnerabilities from occurring in the future.