Techniques › T1132.001 › AN0346
AN0346 Analytic 0346
Linux · attack.mitre.org · ATT&CK Enterprise v19.2
<p>Shell/utility (base64, xxd -p, od, openssl enc -base64, python/perl base64 libraries) encodes data → subsequent outbound connections (curl/wget/bash TCP, socat, python requests) with high asymmetry or Base64/MIME blobs in HTTP/DNS payloads.</p>
- Detects
- T1132.001 Standard Encoding
- Part of
- DET0124 Behavior-chain detection for T1132.001 Data Encoding: Standard Encoding (Base64/Hex/MIME) across Windows, Linux, macOS, ESXi
Log sources and channels
Exactly as MITRE states them in x_mitre_log_source_references. Where a channel is vague, it is vague in the source; kevmap does not tidy it.
| Log source | Channel | Data component |
|---|---|---|
| auditd:SYSCALL | execve of base64|openssl|xxd|python|perl with arguments matching Base64 flags | DC0032 Process Creation |
| WinEventLog:Sysmon | EventCode=3, 22 | DC0082 Network Connection Creation |
| NSM:Flow | http: HTTP body or headers contain long Base64 sections; gzip/deflate + Base64 | DC0085 Network Traffic Content |
Mutable elements
Parameters MITRE marks as environment-specific. These are the knobs you are expected to tune; they are why an analytic is not a rule.
| Field | Description |
|---|---|
EncodingToolsAllowList | Build/backup jobs that legitimately call base64/openssl. |
EntropyThreshold | Shannon entropy for payloads (e.g., >4.5). |
TimeWindow | Join window between exec and egress (default 10m). |
OutInRatio | Bytes_out / bytes_in threshold (default 4). |