Remote code execution in FreePBX Phone Apps module

1) Input validation error

EUVDB-ID: #VU65373

Risk: Critical

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2021-45461

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to insufficient validation of user-supplied input in the Phone Apps (restapps) module for FreePBX. A remote attacker can send specially crafted input to the application and execute arbitrary code on the system.

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Phone Apps: 15.0.19.87 - 16.0.18.41

External links

http://community.freepbx.org/t/security-issue-potential-rest-phone-apps-rce/80109
http://wiki.freepbx.org/display/FOP/2021-12-21+SECURITY%3A+Potential+Rest+Phone+Apps+RCE
http://community.freepbx.org/t/0-day-freepbx-exploit/80092

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.