Authenticated amportal search for ‘freepbx_engine’ in non root writeable directories leads to potential privilege escalation
FreePBX is an open-source web-based graphical user interface (GUI) that manages Asterisk. Prior to versions 16.0.45 and 17.0.24 of the FreePBX framework, an authenticated local privilege escalation exists in the deprecated FreePBX startup script `amportal`. In the deprecated `amportal` utility, the lookup for the `freepbx_engine` file occurs in `/etc/asterisk/` directories. Typically, these are configured by FreePBX as writable by the **asterisk** user and any members of the **asterisk** group. This means that a member of the **asterisk** group can add their own `freepbx_engine` file in `/etc/asterisk/` and upon `amportal` executing, it would exec that file with root permissions (even though the file was created and placed by a non-root user). Version 16.0.45 and 17.0.24 contain a fix for the issue. Other mitigation strategies are also available. Confirm only trusted local OS system users are members of the `asterisk` group. Look for suspicious files in the `/etc/asterisk/` directory (via Admin -> Config Edit in the GUI, or via CLI). Double-check that `live_dangerously = no` is set (or unconfigured, as the default is **no**) in `/etc/asterisk/asterisk.conf` file. Eliminate any unsafe custom use of Asterisk dial plan applications and functions that potentially can manipulate the file system, e.g., System(), FILE(), etc.
Problem Types
| Type | CWE ID | Description |
|---|
| CWE | CWE-426 | CWE-426: Untrusted Search Path |
Type: CWE
Description: CWE-426: Untrusted Search Path
Metrics
| Version | Base score | Base severity | Vector |
|---|
| 4.0 | 5.7 | MEDIUM | CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U |
Version: 4.0
Base score: 5.7
Base severity: MEDIUM
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U