Detection rules › Splunk

Network Connection with Suspicious Folder (Sysmon)

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

Detects potential downloads to suspicious file locations like temp, appdata, and downloads

MITRE ATT&CK coverage

TacticTechniques
Command & Control

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 3: Network connection

Rule body

id: '9019.12092'
title: Network Connection with Suspicious Folder
description: 'Detects potential downloads to suspicious file locations like temp,
  appdata, and downloads. - Threat Actor Association: Alloy Taurus/Gallium, Lazarus,
  NewsPenguin, OilRig, TA413 - Software Association: LOWZERO, Vidar Stealer'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (EventCode=3 OR "Event>ID<3")
  ("Temporary Internet Files" OR TERM("TEMP") OR TERM("Downloads") OR TERM("Appdata"))
  | regex process="(?i)Temp|Downloads|Appdata" | table _time, host, user dest, direction,
  event_id, eventtype, parent_*, process, process_*, user, user_id, src_*, dest_*
  | bin span=1s | stats values(*) as * by _time, host, process '
techniques:
- command-and-control:ingress tool transfer
technique_id: 
- T1105
data_category:
- Process use of network
- Windows Sysmon
references: null

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_sysmon` (EventCode=3 OR "Event>ID<3") ("Temporary Internet Files" OR TERM("TEMP") OR TERM("Downloads") OR TERM("Appdata"))

Stage 2: regex

| regex process="(?i)Temp|Downloads|Appdata"

Stage 3: table

| table _time, host, user dest, direction, event_id, eventtype, parent_*, process, process_*, user, user_id, src_*, dest_*

Stage 4: bucket

| bin span=1s

Stage 5: stats

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

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventCodeeq
  • 3 corpus 24 (splunk 14, kusto 8, chronicle 2)
field:"EventID" kind:eq value:"3"
processregex_match
    • "(?i)Temp
    • Downloads
    • Appdata"
field:"CommandLine" kind:regex_match

Search terms

These SPL tokens match against raw event text.

StageTerm
1"Event>ID<3"
1"Temporary Internet Files"
1"TEMP"
1"Downloads"
1"Appdata"