Detection rules › Splunk
Multiple nslookup commands (Sysmon)
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
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
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
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.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
event_count | gt |
|
process_name | match |
|
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.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>1<" |
| 1 | "nslookup" |
| 1 | "nslookup.exe" |