Zyxel Addressed Firewall Vulnerability

Zyxel has addressed a critical security vulnerability (CVE-2022-30525, CVSS score: 9.8) affecting Zyxel firewall devices that enables unauthenticated and remote attackers to gain arbitrary code execution as the “nobody” user.

The issue was discovered by Rapid7 which reported it on April 13.

Zyxel silently addressed the flaw by releasing security updates on April 28, 2022, Rapid7 pointed out that this choice leaves defenders in the dark and only advantage the attackers.

The affected models vulnerable to unauthenticated and remote command injection via the administrative HTTP interface. Commands are executed as the nobody user.

There are more than 15,000 internet-facing vulnerable systems tracked by the Shodan search engine. The researchers also developed a Metasploit module for this issue and published a PoC of the attack

The vendor the following issues in its VMG3312-T20A wireless router and AP Configurator:

• a command injection (CVE-2022-26413);
• a buffer overflow (CVE-2022-26414)
• a local privilege escalation (CVE-2022-0556) flaw.