[BPFDoor](https://attack.mitre.org/software/S1161) is a Linux based passive long-term backdoor used by China-based threat actors. First seen in 2021, [BPFDoor](https://attack.mitre.org/software/S1161) is named after its usage of Berkley Packet Filter (BPF) to execute single task instructions. [BPFDoor](https://attack.mitre.org/software/S1161) supports multiple protocols for communicating with a C2 including TCP, UDP, and ICMP and can start local or reverse shells that bypass firewalls using iptables.(Citation: Sandfly BPFDoor 2022)(Citation: Deep Instinct BPFDoor 2023)