An issue was discovered in the 3CX Phone System Management Console prior to version 18 Update 3 FINAL. An unauthenticated attacker could abuse improperly secured access to arbitrary files on the server, leading to cleartext credential disclosure. Afterwards, the authenticated attacker is able to upload a file that overwrites a 3CX service binary, leading to Remote Code Execution as NT AUTHORITY\SYSTEM on Windows installations. Versions prior to version 18, Hotfix 1 Build 18.0.3.461 March 2022, are prone to an additional unauthenticated file system access to C:\Windows\System32.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-28005
• https://www.3cx.com/blog/change-log/phone-system-change-log/
• https://www.3cx.com/blog/releases/v18-security-hotfix/
• https://www.3cx.com/blog/releases/v18-update-3-final/
• https://medium.com/@frycos/pwning-3cx-phone-management-backends-from-the-internet-d0096339dd88