Suspicious Download or Exfiltration via Finger LOLBin

ATT&CK techniques

C2

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

What it detects

This rule detects execution of the legacy finger client, an uncommon living-off-the-land binary that attackers repurpose to download payloads and exfiltrate data over the finger protocol. Its use in modern Windows environments is almost always malicious. Finger-based transfers move data across the network while blending with rarely inspected protocol traffic.

Reporting behind it

Related detections9 linkedT1105 — drag to rearrange

Suspicious Data Exfiltration via finger to Remote Host

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 Bash Dev-TCP Reverse Shell Execution

Suspicious Download or Exfiltration via Finger LOLBin

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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