Researchers Raise Alarm for F5 BIG-IP Malware Attacks
The urgency to patch gaping security holes in F5 Networks BIG-IP and BIG-IQ products escalated over the weekend after researchers spotted malicious in-the-wild attack activity.
Malware hunters at U.K.-based NCC Group are raising the alarm for mass scanning and “multiple exploitation attempts” with exploits targeting critical security flaws in the F5 enterprise networking infrastructure products.
The vulnerabilities were patched on March 10 and are considered high-priority fixes because of the risk of exposure to authentication bypass and remote code execution attacks.
Less than a week after the release of the patches, proof-of-concept code started circulating and, over the last weekend, NCC Group’s researchers said its honeypot infrastructure was being hit with exploitation attempts.
“This knowledge, combined with having reproduced the full exploit-chain we assess that a public exploit is likely to be available in the public domain soon,” NCC Group warned.
The researchers explain the exploitation path:
Exploitation of this vulnerability requires two steps. First, authentication has to be bypassed by leveraging the SSRF vulnerability to gain an authenticated session token. This authenticated session can then be used to interact with REST API endpoints, which would otherwise require authentication.
The most useful endpoint for an attacker is the tm/util/bash endpoint, which allows an (authenticated) user to execute commands on the underlying server with root privileges. However, as the REST API is designed for remote administration, there are many endpoints which an attacker might wish to take advantage of.
As part of the F5 patches, a command injection vulnerability was also patched in the tm/access/bundle-install-tasks REST endpoint – which could be used as an alternative way to execute arbitrary commands once authentication has been bypassed.
NCC Group also released Suricata network rules to help defenders mitigate this threat.
The U.S. government’s CISA (Cybersecurity and Infrastructure Security Agency (CISA) also released an advisory to underline the importance of reviewing F5’s advisory and applying the updates.