Zyxel warns of vulnerabilities in a wide range of its products

Networking hardware-maker Zyxel is warning of nearly a dozen vulnerabilities in a wide array of its products. If left unpatched, some of them could enable the complete takeover of the devices, which can be targeted as an initial point of entry into large networks.

The most serious vulnerability, tracked as CVE-2024-7261, can be exploited to “allow an unauthenticated attacker to execute OS commands by sending a crafted cookie to a vulnerable device,” Zyxel warned. The flaw, with a severity rating of 9.8 out of 10, stems from the “improper neutralization of special elements in the parameter ‘host’ in the CGI program” of vulnerable access points and security routers. Nearly 30 Zyxel devices are affected. As is the case with the remaining vulnerabilities in this post, Zyxel is urging customers to patch them as soon as possible.

But wait… there’s more

The hardware manufacturer warned of seven additional vulnerabilities affecting firewall series including the ATP, USG-FLEX, and USG FLEX 50(W)/USG20(W)-VPN. The vulnerabilities carry severity ratings ranging from 4.9 to 8.1. The vulnerabilities are:

CVE-2024-6343: a buffer overflow vulnerability in the CGI program that could allow an authenticated attacker with administrator privileges to wage denial-of-service by sending crafted HTTP requests.

CVE-2024-7203: A post-authentication command injection vulnerability that could allow an authenticated attacker with administrator privileges to run OS commands by executing a crafted CLI command.

CVE-2024-42057: A command injection vulnerability in the IPSec VPN feature that could allow an unauthenticated attacker to run OS commands by sending a crafted username. The attack would be successful only if the device was configured in User-Based-PSK authentication mode and a valid user with a long username exceeding 28 characters exists.

CVE-2024-42058: A null pointer dereference vulnerability in some firewall versions that could allow an unauthenticated attacker to wage DoS attacks by sending crafted packets.

CVE-2024-42059: A post-authentication command injection vulnerability that could allow an authenticated attacker with administrator privileges to run OS commands on an affected device by uploading a crafted compressed language file via FTP.

CVE-2024-42060: A post-authentication command injection vulnerability that could allow an authenticated attacker with administrator privileges to execute OS commands by uploading a crafted internal user agreement file to the vulnerable device.

CVE-2024-42061: A reflected cross-site scripting vulnerability in the CGI program “dynamic_script.cgi” that could allow an attacker to trick a user into visiting a crafted URL with the XSS payload. The attacker could obtain browser-based information if the malicious script is executed on the victim’s browser.

The remaining vulnerability is CVE-2024-5412 with a severity rating of 7.5. It resides in 50 Zyxel product models, including a range of customer premises equipment, fiber optical network terminals, and security routers. A buffer overflow vulnerability in the “libclinkc” library of affected devices could allow an unauthenticated attacker to wage denial-of-service attacks by sending a crafted HTTP request.

In recent years, vulnerabilities in Zyxel devices have regularly come under active attack. Many of the patches are available for download at links listed in the advisories. In a small number of cases, the patches are available through the cloud. Patches for some products are available only by privately contacting the company’s support team.