F5 fixes critical BIG-IP vulnerability, PoC is public (CVE-2023-46747)

CVE-2020-5902 is a critical, unauthenticated remote code execution flaw in the F5 BIG-IP Traffic Management User Interface (TMUI), the appliance's web management console, rooted in a directory/path traversal issue (CWE-22) in undisclosed TMUI pages. It is triggered by sending crafted HTTP(S) requests to the management interface — classically path-traversal URLs beneath the TMUI application on the management port — which lets an attacker bypass authentication, read or delete arbitrary files, and execute commands without credentials. Successful exploitation yields full control of the BIG-IP system, which attackers can use to pivot into networks the appliance fronts, maintain persistence, and deploy ransomware. Any organization running an affected F5 BIG-IP appliance or virtual edition whose TMUI is reachable, or whose management network can be reached, is exposed; F5's installed base spans large enterprises and service providers, so the footprint is broad. Exploitation is confirmed in the wild: the flaw was mass-scanned and exploited within days of its July 2020 disclosure, it is listed in CISA KEV with known ransomware use, and EPSS assigns a ~100% probability of exploitation within 30 days.

Do: Patch immediately using F5's advisory K52145254 — upgrade BIG-IP to a fixed release per the vendor's version matrix, since CISA's required action is applying vendor updates. Until patched, restrict TMUI/management-interface access to trusted source IPs or a VPN (or disable TMUI if unused) and apply F5's published interim workaround. Because ransomware use is confirmed, hunt for indicators of compromise on both patched and unpatched appliances (unexpected files, webshells, modified login pages, new accounts or scheduled tasks) before treating systems as clean.

CVE-2023-46747 is a critical authentication bypass (CVSS 9.8) in the F5 BIG-IP Configuration Utility (TMUI) affecting most BIG-IP modules, including LTM, APM, DNS, AWAF, AFM, ASM, and SSL Orchestrator. By sending undisclosed, specially crafted requests to the TMUI, an attacker with network access to the BIG-IP management port and/or self IP addresses bypasses authentication and can execute arbitrary system commands on the system. No privileges or user interaction are required, and successful exploitation effectively yields full control of the affected BIG-IP deployment. Any organization running vulnerable BIG-IP software is exposed, particularly enterprises, service providers, and government agencies whose management interface or self IPs are reachable. The flaw is being actively exploited: it was added to CISA KEV on 2023-10-31 with known ransomware use, public PoC code exists, and reporting links it to Chinese nation-state actors targeting defense and government networks.

Do: Upgrade all affected BIG-IP systems to the fixed releases identified in F5 advisory K13763 (17.1.0.1, 16.1.4, 15.1.9, 14.1.5.5, or 13.1.5.1 depending on the train, or later); the CISA KEV listing makes remediation mandatory for federal agencies. As an interim mitigation, restrict network access to the TMUI management port and self IP addresses and apply F5's documented mitigation guidance. Given active nation-state and ransomware exploitation, also audit appliances for indicators of compromise such as unexpected accounts, scheduled tasks, and configuration changes.