HAMMERTOSS
HAMMERTOSS is a backdoor that was used by APT29 in 2015. [1] [2]
Techniques Used
| Domain | ID | Name | Use | |
|---|---|---|---|---|
| Enterprise | T1071 | .001 | Application Layer Protocol: Web Protocols |
The "Uploader" variant of HAMMERTOSS visits a hard-coded server over HTTP/S to download the images HAMMERTOSS uses to receive commands.[1] |
| Enterprise | T1059 | .001 | Command and Scripting Interpreter: PowerShell |
HAMMERTOSS is known to use PowerShell.[1] |
| Enterprise | T1001 | .002 | Data Obfuscation: Steganography |
HAMMERTOSS is controlled via commands that are appended to image files.[1] |
| Enterprise | T1573 | .001 | Encrypted Channel: Symmetric Cryptography |
Before being appended to image files, HAMMERTOSS commands are encrypted with a key composed of both a hard-coded value and a string contained on that day's tweet. To decrypt the commands, an investigator would need access to the intended malware sample, the day's tweet, and the image file containing the command.[1] |
| Enterprise | T1567 | .002 | Exfiltration Over Web Service: Exfiltration to Cloud Storage |
HAMMERTOSS exfiltrates data by uploading it to accounts created by the actors on Web cloud storage providers for the adversaries to retrieve later.[1] |
| Enterprise | T1564 | .003 | Hide Artifacts: Hidden Window |
HAMMERTOSS has used |
| Enterprise | T1102 | .003 | Web Service: One-Way Communication |
The "tDiscoverer" variant of HAMMERTOSS establishes a C2 channel by downloading resources from Web services like Twitter and GitHub. HAMMERTOSS binaries contain an algorithm that generates a different Twitter handle for the malware to check for instructions every day.[1] |