Cisco Small Business RV320 and RV325 Routers: information disclosure flaw under attack

What is affected

Cisco Small Business RV320 and RV325 Routers are mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have them yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Cisco Small Business RV320 and RV325 Dual Gigabit WAN VPN Routers contain improper access controls for URLs. Exploitation could allow an attacker to download the router configuration or detailed diagnostic information.

What an attacker can do

This is a information disclosure flaw. It lets an attacker read data they are not supposed to see, such as memory contents, credentials or internal files. It is often the first step of a larger attack.

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. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
2. If you administer Cisco Small Business RV320 and RV325 Routers at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply updates per vendor instructions.

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on November 3, 2021, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by May 3, 2022, 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 100% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 100.0% of all scored vulnerabilities.

Its CVSS severity score is 7.5 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

A vulnerability in the web-based management interface of Cisco Small Business RV320 and RV325 Dual Gigabit WAN VPN Routers could allow an unauthenticated, remote attacker to retrieve sensitive information. The vulnerability is due to improper access controls for URLs. An attacker could exploit this vulnerability by connecting to an affected device via HTTP or HTTPS and requesting specific URLs. A successful exploit could allow the attacker to download the router configuration or detailed diagnostic information. Cisco has released firmware updates that address this vulnerability.