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Authentication Bypass Leading to SQL Injection and RCE

Critical
chrsmj published GHSA-m42g-xg4c-5f3h Aug 28, 2025

Package

endpoint (FreePBX 15)

Affected versions

< 15.0.66

Patched versions

15.0.66
endpoint (FreePBX 16)
< 16.0.89
16.0.89
endpoint (FreePBX 17)
< 17.0.3
17.0.3

Description

Summary

Insufficiently sanitized user-supplied data allows unauthenticated access to FreePBX Administrator leading to arbitrary database manipulation and remote code execution.

Details

Starting on or before August 21st, 2025, an unauthorized user began accessing multiple FreePBX version 16 and 17 systems that were connected directly to the public internet -- systems with inadequate IP filtering/ACLs -- by exploiting a validation/sanitization error in the processing of user-supplied input to the commercial "endpoint" module. This initial entry point was then chained with several other steps to ultimately gain potentially root level access on the target systems.

Mitigation

Users should upgrade to the latest supported versions of FreePBX (currently 15, 16, and 17) and confirm that the installed "endpoint" module meets the minimum patched versions. Systems not configured for automatic updates, or those wishing to manually update, can do so via the Administrator Control Panel menu Admin -> Module Admin or via generic command line method of updating all modules:

$ fwconsole ma upgradeall

Then checking for the "endpoint" module version number:

$ fwconsole ma list | grep endpoint

Further steps, including suggestions for IOC inspection and Firewall configuration, as well as corner-case considerations, are available in the FreePBX Community Forums under the "Security Advisory: Please Lock Down Your Administrator Access" topic at https://community.freepbx.org/t/security-advisory-please-lock-down-your-administrator-access/107203

Affected Versions

All supported versions of FreePBX: 15, 16, and 17.
EOL versions are untested for this vulnerability but may be affected. It is recommended to upgrade EOL versions to a supported version to ensure this vulnerability -- and potentially other published security vulnerabilities -- are not present.

Indicators Of Compromise

This is a summary of the current IOCs listed in the forum topic linked above as of this writing:

  • File /etc/freepbx.conf recently modified or missing
  • File /var/www/html/.clean.sh should not exist on normal systems
  • POST requests to modular.php in web server logs likely not legitimate traffic
  • Phone calls placed to extension 9998 in call logs and CDRs are unusual - unless previously configured
  • Suspicious ampuser user in the ampusers database table or other unknown users

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality High
Integrity High
Availability High

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVE ID

CVE-2025-57819

Weaknesses

Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Learn more on MITRE.

Authentication Bypass Using an Alternate Path or Channel

A product requires authentication, but the product has an alternate path or channel that does not require authentication. Learn more on MITRE.

Credits