Suspicious Data Exfiltration via finger to Remote Host

ATT&CK techniques

C2 → Exfiltration

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
- T1048.003Exfiltration Over Unencrypted Non-C2 Protocol
Impact

What it detects

This rule detects execution of the legacy finger client against a remote host, abused in this case to exfiltrate directory and task listings and to pull down content over TCP port 79. The finger utility has virtually no legitimate use on modern Windows, so its execution against an external host indicates a living-off-the-land exfiltration or download channel.

Reporting behind it

Related detections9 linkedT1105 — drag to rearrange

Suspicious Data Transfer via curl to Raw IP Address

Suspicious Download or Exfiltration via Finger LOLBin

Suspicious File Download via PowerShell WebClient DownloadFile

Suspicious Remote HTA Execution via mshta over HTTP

Suspicious Encoded PowerShell DownloadString Execution

Malicious Remote MSI Install of RuntimeBroker via msiexec

Suspicious File Download via certutil urlcache

Suspicious Remote MSI Installation via msiexec from HTTP URL

Suspicious PowerShell Download Cradle via Invoke-WebRequest Piped to iex (via process_creation)

Suspicious Data Exfiltration via finger to Remote Host

Pivot detection · T1105 · 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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