CVE-2024-53564 is a security vulnerability identified in Sangoma's FreePBX version 17.0.19.17, categorized under CWE-434, which concerns unrestricted upload of files with dangerous types. The vulnerability arises because FreePBX does not verify the file type of uploaded modules, allowing users with high administrative privileges to upload arbitrary files without restriction. This could potentially lead to insertion of malicious files or modules that might alter system behavior or compromise system integrity. However, the supplier's position clarifies that this vulnerability does not increase risk beyond what is already possible by high-privilege administrators, implying that the threat is limited to insider misuse or compromised admin accounts. The CVSS 3.1 base score is 2.2, reflecting low severity due to the requirement of high privileges (PR:H), network attack vector (AV:N), high attack complexity (AC:H), no user interaction (UI:N), and limited impact on integrity (I:L) without affecting confidentiality or availability. No known exploits have been reported in the wild, and no official patches have been released at the time of publication. This vulnerability highlights the importance of strict administrative access controls and monitoring in FreePBX deployments.

The impact of CVE-2024-53564 is primarily limited to organizations using FreePBX version 17.0.19.17 where high-privilege administrators have the ability to upload modules. Since the vulnerability requires high-level privileges, the risk of external attackers exploiting it directly is minimal unless they first compromise an admin account. If exploited by a malicious insider or through a compromised admin, attackers could upload unauthorized files that may alter system behavior, introduce backdoors, or facilitate further attacks within the telephony infrastructure. This could lead to integrity issues, potential service disruptions, or unauthorized access to sensitive telephony data. However, confidentiality and availability impacts are considered negligible based on current information. The low CVSS score reflects the limited scope and difficulty of exploitation. Organizations with weak administrative controls or insufficient monitoring may face higher risks. The absence of known exploits reduces immediate threat but does not eliminate the need for vigilance.

To mitigate CVE-2024-53564, organizations should implement strict administrative access controls, ensuring only trusted personnel have high-privilege rights in FreePBX. Employ multi-factor authentication (MFA) for admin accounts to reduce the risk of account compromise. Regularly audit and monitor module uploads and administrative activities to detect unauthorized or suspicious file uploads promptly. Consider restricting module upload capabilities to a minimal set of administrators and enforce change management policies for module installation. If possible, upgrade to a FreePBX version where this vulnerability is addressed once a patch becomes available. In the interim, apply compensating controls such as network segmentation to limit access to the FreePBX administrative interface and use intrusion detection systems to monitor for anomalous behavior. Educate administrators about the risks of uploading unverified modules and enforce the use of only trusted, verified modules.