T1132
Data Encoding
ESXi · Linux · macOS · Windowsnothing on this site yetT1132 on attack.mitre.org
Adversaries may encode data to make the content of command and control traffic more difficult to detect. Command and control (C2) information can be encoded using a standard data encoding system. Use of data encoding may adhere to existing protocol specifications and includes use of ASCII, Unicode, Base64, MIME, or other binary-to-text and character encoding systems. Some data encoding systems may also result in data compression, such as gzip.
how MITRE says to see it
Detection Strategy for Data Encoding in C2 Channels
- Atypical processes (e.g., powershell.exe, regsvr32.exe) encode large outbound traffic using Base64 or other character encodings; this traffic is sent over uncommon ports or embedded in protocol fields (e.g., HTTP cookies or headers).
- Custom scripts or processes encode outbound traffic using gzip, Base64, or hex prior to exfiltration via curl, wget, or custom sockets. Encoding typically occurs before or during outbound connections from non-network daemons.
- Processes use built-in encoding utilities (e.g., `base64`, `xxd`, or `plutil`) to encode file contents followed by HTTP/HTTPS transfer via curl or custom applications.
- ESXi daemons (e.g., hostd, vpxa) are wrapped or impersonated to send large outbound traffic using gzip/Base64 encoding over SSH or HTTP. These actions follow suspicious logins or shell access.
what reduces it
- M1031 Network Intrusion Prevention. Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific obfuscation technique used by a particular adversary or tool, and will likely be different across various malware families and versions.