Detection rules › Splunk

Finger Execution (Windows Event Log)

Group by
_time, host
Source
github.com/anvilogic-forge/armory

Finger.exe, a command that ships with Windows to retrieve information about users on remote computers running the Finger service or daemon. Communication is carried via the Name/Finger network communication protocol.As this is a common component on Windows, it can be leveraged to perform living-off-the-land attacks

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1105 Ingress Tool Transfer

References

Event coverage

Rule body yaml

id: '7833.9440'
title: Finger Execution
description: 'Finger.exe, a command that ships with Windows to retrieve information
  about users on remote computers running the Finger service or daemon. Communication
  is carried via the Name/Finger network communication protocol.As this is a common
  component on Windows, it can be leveraged to perform living-off-the-land attacks.
  -- Living Off the Land Binary and Scripts (LOLBAS) (LOLBIN) -- Software Association:
  MINEBRIDGE -- Atomics T1105 Test #16 '
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
  "<EventID>4688<" OR Type=Process) ("finger.exe" OR (".exe" "@")) | table _time,
  host, user process, process_*, signature_id, parent_* | bin span=1s | stats values(*)
  as * by _time, host | where match(process_name,"(?i)finger") OR match(process,"(?i)(finger)|\S+@(.*?\.\w{2,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})") '
techniques:
- command-and-control:ingress tool transfer
technique_id: 
- T1105
data_category:
- Windows event logs
references:
- https://dmfrsecurity.com/2020/12/31/using-finger-exe-to-transfer-files/
- https://strontic.github.io/xcyclopedia/library/finger.exe-8E9AFA491D704EAF9183B15A189BBDE2.html

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) ("finger.exe" OR (".exe" "@"))

Stage 2: table

| table _time, host, user process, process_*, signature_id, parent_*

Stage 3: bucket

| bin span=1s

Stage 4: stats

| stats values(*) as * by _time, host

Stage 5: where

| where match(process_name,"(?i)finger") OR match(process,"(?i)(finger)|\S+@(.*?\.\w{2,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})")

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 4688 corpus 313 (splunk 283, kusto 30)
processmatch
  • "(?i)(finger)|\S+@(.*?\.\w{2,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})" corpus 2 (splunk 2)
process_namematch
  • "(?i)finger" corpus 2 (splunk 2)

Search terms

Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.

StageTerm
1TERM
1"<EventID>4688<"
1"finger.exe"
1".exe"
1"@"