S1224 CASTLETAP
CASTLETAP is an ICMP port knocking backdoor that has been installed on compromised FortiGate firewalls by UNC3886.1
| Item | Value |
|---|---|
| ID | S1224 |
| Associated Names | |
| Type | MALWARE |
| Version | 1.0 |
| Created | 16 June 2025 |
| Last Modified | 16 June 2025 |
| Navigation Layer | View In ATT&CK® Navigator |
Techniques Used
| Domain | ID | Name | Use |
|---|---|---|---|
| enterprise | T1059 | Command and Scripting Interpreter | - |
| enterprise | T1059.004 | Unix Shell | CASTLETAP has the ability to spawn BusyBox command shell in victim environments.1 |
| enterprise | T1005 | Data from Local System | CASTLETAP can execute a C2 command to transfer files from victim machines.1 |
| enterprise | T1140 | Deobfuscate/Decode Files or Information | CASTLETAP can filter and deobfuscate an XOR encrypted activation string in the payload of an ICMP echo request.1 |
| enterprise | T1573 | Encrypted Channel | - |
| enterprise | T1573.001 | Symmetric Cryptography | CASTLETAP can receive a 9-byte XOR encrypted activation string in the payload of an ICMP echo request packet.1 |
| enterprise | T1573.002 | Asymmetric Cryptography | CASTLETAP can initiate a C2 connection over an SSL socket.1 |
| enterprise | T1105 | Ingress Tool Transfer | CASTLETAP can transfer files to compromised network devices.1 |
| enterprise | T1040 | Network Sniffing | CASTLETAP has the ability to create a raw promiscuous socket to sniff network traffic.1 |
| enterprise | T1205 | Traffic Signaling | - |
| enterprise | T1205.002 | Socket Filters | CASTLETAP can listen for a specialized ICMP packet for activation on compromised network devices.1 |
Groups That Use This Software
| ID | Name | References |
|---|---|---|
| G1048 | UNC3886 | 1 |