Detection rules › Splunk

System Time enumeration (Windows Event Log)

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

An adversary may gather the system time and/or time zone from a local or remote system. The system time is set and stored by the Windows Time Service within a domain to maintain time synchronization between systems and services in an enterprise network. This use case looks for net time executions

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1124 System Time Discovery

References

Event coverage

Rule body yaml

id: '8151.10003'
title: System Time enumeration
description: 'An adversary may gather the system time and/or time zone from a local
  or remote system. The system time is set and stored by the Windows Time Service
  within a domain to maintain time synchronization between systems and services in
  an enterprise network. This use case looks for net time executions. -- Threat Actor
  Association: APT28 (aka.Fancy Bear, Fighting Ursa, Forest Blizzard, Pawn Storm,
  TA422, STRONTIUM) - Software Association: Conti'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
  "<EventID>4688<" OR Type=Process) "net" TERM(time) | regex process="(?i)net.*?time.*?\x5c\x5c"
  | table _time, host, user process, process_*, signature_id, parent_* | bin span=1s
  | stats values(*) as * by _time, host '
techniques:
- discovery:system time discovery
technique_id: 
- T1124
data_category:
- Windows event logs
- Process command-line parameters
references:
- https://research.nccgroup.com/2021/01/12/abusing-cloud-services-to-fly-under-the-radar/

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) "net" TERM(time)

Stage 2: regex

| regex process="(?i)net.*?time.*?\x5c\x5c"

Stage 3: table

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

Stage 4: bucket

| bin span=1s

Stage 5: stats

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

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)
processregex_match
  • "(?i)net.*?time.*?\x5c\x5c"

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"net"
1TERM
1time