Adversaries may compress and/or encrypt data that is collected prior to exfiltration. Compressing data can help to obfuscate its contents and minimize use of network resources. Encryption can be used to hide information that is being exfiltrated from detection or make exfiltration less conspicuous upon inspection by a defender.
Both compression and encryption are done prior to exfiltration, and can be performed using a utility, programming library, or custom algorithm.
| ID | Name | Description |
|---|---|---|
| S0422 | Anubis |
Anubis exfiltrates data encrypted (with RC4) by its ransomware module.[1] |
| S0540 | Asacub |
Asacub has encrypted C2 communications using Base64-encoded RC4.[2] |
| S1079 | BOULDSPY | |
| S1094 | BRATA |
BRATA has compressed data with the |
| C0033 | C0033 |
During C0033, PROMETHIUM used StrongPity to exfiltrate encrypted data to the C2 server.[5] |
| S0505 | Desert Scorpion |
Desert Scorpion can encrypt exfiltrated data.[6] |
| S0405 | Exodus |
Exodus One encrypts data using XOR prior to exfiltration.[7] |
| S0577 | FrozenCell |
FrozenCell has compressed and encrypted data before exfiltration using password protected .7z archives.[8] |
| S0535 | Golden Cup |
Golden Cup has encrypted exfiltrated data using AES in ECB mode.[9] |
| S0421 | GolfSpy |
GolfSpy encrypts data using a simple XOR operation with a pre-configured key prior to exfiltration.[10] |
| S1082 | Sunbird | |
| S0424 | Triada |
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Many encryption mechanisms are built into standard application-accessible APIs and are therefore undetectable to the end user.