Pierluigi Paganini May 26, 2022

Zyxel addressed multiple vulnerabilities impacting many of its products, including APs, AP controllers, and firewalls.

Zyxel has released security updates to address multiple vulnerabilities affecting multiple products, including firewall, AP, and AP controller products.

Below is the list of the four vulnerabilities, the most severe one is a command injection flaw in some CLI commands tracked as CVE-2022-26532 (CVSS v3.1 7.8):

• CVE-2022-0734: A cross-site scripting vulnerability was identified in the CGI program of some firewall versions that could allow an attacker to obtain some information stored in the user’s browser, such as cookies or session tokens, via a malicious script.
• CVE-2022-26531: Multiple improper input validation flaws were identified in some CLI commands of some firewall, AP controller, and AP versions that could allow a local authenticated attacker to cause a buffer overflow or a system crash via a crafted payload.
• CVE-2022-26532: A command injection vulnerability in the “packet-trace” CLI command of some firewall, AP controller, and AP versions could allow a local authenticated attacker to execute arbitrary OS commands by including crafted arguments to the command.
• CVE-2022-0910: An authentication bypass vulnerability caused by the lack of a proper access control mechanism has been found in the CGI program of some firewall versions. The flaw could allow an attacker to downgrade from two-factor authentication to one-factor authentication via an IPsec VPN client.

According to the advisory published by the vendor, the issues affect USG/ZyWALL, USG FLEX, ATP, VPN, NSG firewalls, NXC2500 and NXC5500 AP controllers, and NAP, NWA, WAC, and WAX Access Point families.

The vendor has already released security patched to address the flaws for most of the affected models.

The hotfix for NXC2500 AP controllers affected by CVE-2022-26531 and CVE-2022-26532 must be requested from a local service representative.

Experts urge admins to upgrade their installs to avoid cyber attacks exploiting the above flaws.

This advice is especially important for US companies as we head into a holiday weekend when it is common for threat actors to conduct attacks.

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Pierluigi Paganini

(SecurityAffairs – hacking, Zyxel)

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