Malicious Base64 Decoded Shell Payload Execution

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.004Unix Shell
Persistence
Priv Esc
Defense Evasion
- T1140Deobfuscate/Decode Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects a base64-decoded command being piped directly into a shell, the second-stage delivery pattern seen after Log4Shell LDAP/JNDI exploitation. Post-exploitation payloads decode an encoded command with base64 -d and pipe it to bash to fetch and run miner or botnet droppers while evading plaintext detection.

Reporting behind it

Related detections9 linkedT1140 — drag to rearrange

Suspicious Bash Decode Chain Using curl xxd and base64 Piped to eval via Linux Shell

Suspicious Base64 Decoded Payload Piped to Shell on Linux

Suspicious Base64 Decoding Piped to Shell on macOS

Suspicious Hex Decoding Piped to Shell via xxd on macOS

Malicious Shell Payload Piped from curl to zsh

Obfuscated Base64-Decoded Payload Piped to a Shell (via process_creation)

Obfuscated Base64-Decoded Payload Piped to Shell via macOS ClickFix Terminal Lure (via process_creation)

Suspicious awk Character Generation Piped to Shell on VMware ESXi (via process_creation)

Suspicious certutil Decode or Remote Download

Malicious Base64 Decoded Shell Payload Execution

Pivot detection · T1140 · 9 related

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