Mitel 6800 and 6900 Series SIP phone devices through 2022-04-27 have "undocumented functionality." A vulnerability in Mitel 6800 Series and 6900 Series SIP phones excluding 6970, versions 5.1 SP8 (5.1.0.8016) and earlier, and 6.0 (6.0.0.368) through 6.1 HF4 (6.1.0.165), could allow a unauthenticated attacker with physical access to the phone to gain root access due to insufficient access control for test functionality during system startup. A successful exploit could allow access to sensitive information and code execution.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-29855
• https://www.mitel.com/support/security-advisories
• https://www.mitel.com/support/security-advisories/mitel-product-security-advisory-22-0004
• https://www.syss.de/pentest-blog/undocumented-functionality-backdoor-in-mitel-desk-phones-syss-2022-021
• http://seclists.org/fulldisclosure/2022/Jun/32
• http://packetstormsecurity.com/files/167547/Mitel-6800-6900-Series-SIP-Phones-Backdoor-Access.html