Array Networks AG/vxAG ArrayOS: authentication bypass flaw under attack

What is affected

Array Networks AG/vxAG ArrayOS is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Array Networks AG and vxAG ArrayOS contain a missing authentication for critical function vulnerability that allows an attacker to read local files and execute code on the SSL VPN gateway.

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

CISA records this vulnerability as known to be used in ransomware campaigns: attackers use it to get in, then encrypt files and demand payment.

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 Array Networks AG/vxAG ArrayOS 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 mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• support.arraynetworks.netsupport.arraynetworks.net/prx/001/http/supportportal.arraynetworks.net/documentation/Field

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on November 25, 2024, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by December 16, 2024, 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 68% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.3% 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

Array Networks Array AG Series and vxAG (9.4.0.481 and earlier) allow remote code execution. An attacker can browse the filesystem on the SSL VPN gateway using a flags attribute in an HTTP header without authentication. The product could then be exploited through a vulnerable URL. The 2023-03-09 vendor advisory stated "a new Array AG release with the fix will be available soon."