Undocumented admin-level backdoor discovered in Zyxel security products

Shawn Knight

Posts: 13,436   +132
Staff member
What just happened? Researchers from cyber security specialist Eye recently uncovered a secret backdoor introduced in a recent firmware update for various Zyxel firewalls and AP controllers. The hardcoded credential vulnerability consists of an undocumented user account complete with plaintext password.

According to Eye, the account grants admin privileges and works on both the SSH and web interface.

Eye said an attacker could use the credentials to change firewall settings to block or allow certain traffic. VPN accounts could also be created to gain access to the network behind the device. When combined with other vulnerabilities like Zerologon, “this could be devastating to small and medium businesses.”

The security firm said more than 100,000 Zyxel devices have their web interface exposed to the Internet.

Zyxel in a security advisory said the account was designed to deliver automatic firmware updates to connected access points through FTP.

Vulnerable products include the ATP, USG, USG FLEX and VPN series of firewalls running firmware ZLD V4.60. NXC2500 and NXC5500 AP controllers running firmware V6.00 through V6.10 are also impacted.

Eye immediately notified Zyxel about the undocumented account and in less than two weeks, the company released updated firmware to fix this and other issues impacting the firewalls. According to Zyxel, a patch to fix the AP controllers will be released on January 8.

Image credit Pixabay

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DZillaXx

Posts: 327   +447
Cheap and "high security" are always mutually exclusive. Any device sold for pennies on the dollar isn't going to protect you against anyone that wants to get in to your network.

Are you trying to say Zyxel hardware is Cheap?...

They make enterprise grade hardware. And while they are not my goto devices, iirc they are very much high quality devices. While I prefer Cisco for larger projects, they have had their fair share of backdoors in the past.

These days when talking about cheap commercial grade equipment Ubiquiti tends to be one of the most popular.
 

DrSuess

Posts: 134   +105
Cheap and "high security" are always mutually exclusive. Any device sold for pennies on the dollar isn't going to protect you against anyone that wants to get in to your network.
Have you ever owned one? If not you can't call or imply they are cheap products with out evidence to support your assertation.
 

ColdSoup

Posts: 112   +241
Are you trying to say Zyxel hardware is Cheap?...

These days when talking about cheap commercial grade equipment Ubiquiti tends to be one of the most popular.

Yes. It is cheap. Objectively it costs a lot less than competing products.
 

ColdSoup

Posts: 112   +241
Have you ever owned one? If not you can't call or imply they are cheap products with out evidence to support your assertation.

No point in arguing with you if you can't understand that $1000 < $10,000. Zyxel products are objectively cheap compared to similar hardware marketed to large enterprise.