Multiple nslookup commands (Sysmon)

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

Threat actors have been observed gathering host based network information by running a batch script, which ran nslookup for each host in the environment

MITRE ATT&CK coverage

Tactic	Techniques
Discovery	`T1016` System Network Configuration Discovery `T1018` Remote System Discovery

References

https://thedfirreport.com/2022/04/25/quantum-ransomware/

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

id: '12915.18551'
title: Multiple nslookup commands
description: 'Threat actors have been observed gathering host based network information
  by running a batch script, which ran nslookup for each host in the environment.Living
  Off the Land Binary and Scripts (LOLBAS) (LOLBIN) -- Software Association: Rhysida'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
  ("nslookup" OR "nslookup.exe") | table _time, host, user process, process_*, signature_id,
  parent_* | bin span=60s | stats values(*) as * by _time, host | where match(process_name,
  "(?i)nslookup.exe") and event_count > 2 '
techniques:
- discovery:system network configuration discovery
- discovery:remote system discovery
technique_id: 
- T1016
- T1018
data_category:
- Windows Sysmon
references:
- https://thedfirreport.com/2022/04/25/quantum-ransomware/

Stages and Predicates

Stage 1: `search`

`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<") ("nslookup" OR "nslookup.exe")

Stage 2: `table`

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

Stage 3: `bucket`

| bin span=60s

Stage 4: `stats`

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

Stage 5: `where`

| where match(process_name, "(?i)nslookup.exe") and event_count > 2

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`EventCode`	eq	`1` corpus 241 (splunk 225, kusto 15, elastic 1)	`field:"EventID" kind:eq value:"1"`
`event_count`	gt	`2` corpus 3 (splunk 3)	`field:"event_count" kind:gt value:"2"`
`process_name`	regex_match	`"(?i)nslookup.exe"` corpus 2 (splunk 2)	`field:"process_name" kind:regex_match`

Search terms

These SPL tokens match against raw event text.

Stage	Term
1	`"<EventID>1<"`
1	`"nslookup"`
1	`"nslookup.exe"`