Adversaries may communicate using application layer protocols associated with transferring files to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server. Protocols such as SMB1, FTP2, FTPS, and TFTP that transfer files may be very common in environments. Packets produced from these protocols may have many fields and headers in which data can be concealed. Data could also be concealed within the transferred files. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.
- US-CERT TA18-074A
- ESET Machete July 2019
Groups using this technique
| Group | Name | Country |
|---|---|---|
| grp_g0083 | SilverTerrier | — |
| grp_g1054 | MirrorFace | — |
| grp_g1045 | Salt Typhoon | — |
| grp_g0035 | Dragonfly | Russia |
| grp_g0094 | Kimsuky | DPRK |
| grp_g0096 | APT41 | China |
Claims
No public claim points at this technique yet.
Auto-ingested and not human-reviewed; confidence and validity read by citation.