Suspicious tmp Download and Execute Chain on Embedded Linux

ATT&CK techniques

Execution → C2

Recon
Resource Dev
Initial Access
Execution
- T1059.004Unix Shell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects a shell chain that changes into the tmp directory fetches a payload with wget grants it full permissions with chmod and executes it which is the classic Mirai infection sequence on DVR and IoT devices. This variant uses it to deploy an ARM Mirai bot after exploiting CVE-2024-3721. The download and chmod and execute pattern in tmp is a strong IoT botnet indicator.

Reporting behind it

Related detections9 linkedT1059.004 — drag to rearrange

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HamsaUpdate Linux Payload Download via Wget Piped to Bash (via process_creation)

Malicious Curl to Shell Dropper from Paste Site via Command Line

Malicious kagent RAT Delivery via HuggingFace Space Download (via process_creation)

Suspicious Remote Script Execution via curl Piped to bash with nohup on macOS (via process_creation)

Suspicious Botnet Payload Drop to Hidden Xdiag Temp Path

Suspicious tmp Download and Execute Chain on Embedded Linux

Pivot detection · T1059.004 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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