F5 Networks BIG-IP flaw is the latest to be exploited by hackers

Hackers are scanning the web for exposed and unpatched networking devices that fall under F5 Networks’ BIG-IP family of hardware and software products to gain access to vulnerable corporate networks.

A fortnight ago, F5 warned users about seven remote code execution vulnerabilities in its BIG-IP products, including four that were rated ‘critical’. Although fixes were released, researchers with NCC Group have now found evidence that cyber criminals have deployed a full chain exploitation against one of these flaws, tracked as CVE-2021-22986.

The remote code execution flaw, rated 9.8 on the CVSS threat severity scale, lies in the iControl REST interface for the BIG-IP family, and also affects the firm’s BIG-IQ products. Attackers are exploiting the vulnerability to execute arbitrary commands, create and delete files as well as disable services without authentication.

This was the second most severe bug that F5 patched after the 9.9-rated CVE-2021-22987, which manifested in the traffic management user interface (TMUI) when running BIG-IP in Appliance Mode.

“We strongly recommend that all customers update their BIG-IP and BIG-IQ deployments to a fixed version as soon as possible - this is the only way to fully address the vulnerabilities,” said F5 Networks’ SVP and GM for the Application Delivery Controller (ADC) business unit, Kara Spraque.

“If you cannot update your systems immediately, we advise you to apply any additional mitigation recommendations detailed in the security advisories while developing a plan to complete the updates.”

This is the 16th actively-exploited vulnerability identified in 2021, joining an expanding list that includes three vulnerabilities in Google Chrome, as well as four Microsoft Exchange Server flaws that devastated a string of businesses.

The discovery of this full chain exploitation follows several proofs-of-concept for exploitation methods against the F5 Networks vulnerability.

Over the last few days, NCC Group has detected a rise in scanning activity, and multiple exploitation attempts against honeypot infrastructure that researchers had set up to monitor malicious activity. This knowledge has led them to believe that a public exploit is likely to be in the public domain very shortly.

Researchers with Unit 42, meanwhile, have seen evidence that a variant of the Mirai botnet has attempted to exploit CVE-2021-22986, as well as CVE-2020-28188, a remote code execution flaw in the TerraMaster operating system for storage appliances. This latter was discovered last year.