F5 BIG-IP Source Code Leak Tied to State-Linked Campaigns Using BRICKSTORM Backdoor
A China-linked threat cluster, UNC5221, is actively targeting organizations using F5 BIG-IP following a confirmed breach of F5's internal development data. The stolen data includes portions of BIG-IP source code and vulnerability information, raising the risk of rapid 0-day discovery and weaponization. CISA issued an Emergency Directive warning of an imminent threat to federal networks. The attackers deployed a Go-based ELF backdoor called BRICKSTORM, which establishes a persistent C2 tunnel using WebSocket and employs various techniques to evade detection. The backdoor can turn a BIG-IP device into a stealth egress point and internal proxy. F5 has disclosed over twenty vulnerabilities affecting various products, urging immediate patching and security measures.
Pulse ID: 68fb5e503fa25f51c259d28e
Pulse Link: https://otx.alienvault.com/pulse/68fb5e503fa25f51c259d28e
Pulse Author: AlienVault
Created: 2025-10-24 11:09:04
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