Zyxel NAS Devices are Affected by a Critical RCE Vulnerability

Zyxel has announced fixes for a severe format string issue in its network attached storage products. The Taiwanese network giant’s affected products are listed as: 

• NAS326 (V5.21(AAZF.11)C0 and earlier) 
• NAS540 (V5.21(AATB.8)C0 and earlier) 
• NAS542 (V5.21(ABAG.8)C0 and earlier) 

The vulnerability is labeled as CVE-2022-34747 and has a CVSS score of 9.8 regarding the fact that it can lead to remote code execution. The vulnerability resides in a specific binary within the affected products. An unauthorized remote attacker can exploit the vulnerability by utilizing specially crafted UDP packets to execute arbitrary code.

Other Vulnerabilities Zyxel Has Previously Fixed 

The statement comes after Zyxel fixed two security issues impacting its firewall devices in July: CVE-2022-30526 and CVE-2022-2030, which are local privilege escalation and authenticated directory traversal vulnerabilities. 

The company also fixed a security flaw (CVE-2022-0823) in June 2022 that made switches in the GS1200 series vulnerable to timing side-channel attacks used to guess passwords. 

Zyxel released an advisory about CVE-2022-34747 to warn its customers days after QNAP issued a warning about a DeadBolt ransomware attack. DeadBolt targeted NAS devices by exploiting a zero-day vulnerability in the Photo Station software.

Mitigation 

It’s becoming a growing trend to hack NAS devices. Installing updates is a priority. You can find firmware updates for each affected product on Zyxel’s security advisory.