Suspicious Bash Loopback Reconnaissance via curl Header Request

ATT&CK techniques

Execution

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

What it detects

This rule detects bash spawning curl with a header-only request against the loopback address 127.0.0.1, a reconnaissance behavior observed in a Huntress Linux intrusion tied to cryptomining deployment. Attackers probe locally bound services to fingerprint the host and running listeners before staging further tooling. Loopback curl header probes from a shell are unusual for legitimate administration and warrant review.

Reporting behind it

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Suspicious Bash Loopback Reconnaissance via curl Header Request

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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