NUUO NVRmini2 Devices: authentication bypass flaw under attack

What is affected

NUUO NVRmini2 Devices are the kind of equipment many homes and small offices run for years without touching: a router, camera or storage box. Attackers scan the internet for exposed units, and a hijacked one can spy on traffic or be enrolled in a botnet without any visible sign.

NUUO NVRmini2 devices contain a missing authentication vulnerability that allows an unauthenticated attacker to upload an encrypted TAR archive, which can be abused to add arbitrary users.

What an attacker can do

This is a authentication bypass flaw. It lets an attacker get in without a valid username and password and act as a legitimate user, often as an administrator.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Check whether you own this device: look at the label on your router, camera or NAS, or open its admin page and note the model and firmware version.
2. Install the latest firmware from the manufacturer's support page or the device's own update menu.
3. If the manufacturer no longer releases updates for the model, replace it. An end-of-life device with an exploited flaw cannot be made safe.
4. Turn off remote administration from the internet unless you truly need it, and change the default admin password.

The impacted product is end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue utilization of the product.

Vendor advisories and fixes

• nuuo.comnuuo.com/wp-content/uploads/2023/03/NUUO-EOL-letter＿NVRmini-2-and-NVRsolo-series.pdf

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on December 18, 2024, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by January 8, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 48% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99% of all scored vulnerabilities.

Its CVSS severity score is 9.8 out of 10 (critical), as recorded in the US National Vulnerability Database.

Technical description

NUUO NVRmini2 through 3.11 allows an unauthenticated attacker to upload an encrypted TAR archive, which can be abused to add arbitrary users because of the lack of handle_import_user.php authentication. When combined with another flaw (CVE-2011-5325), it is possible to overwrite arbitrary files under the web root and achieve code execution as root.