Detection rules › Splunk

Timestamp Manipulation (Windows Event Log)

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

Adversaries may modify file time attributes to hide new or changes to existing files. Timestomping is a technique that modifies the timestamps of a file (the modify, access, create, and change times), often to mimic files that are in the same folder

MITRE ATT&CK coverage

References

Event coverage

Rule body yaml

id: '8961.20833'
title: Timestamp Manipulation
description: 'Adversaries may modify file time attributes to hide new or changes to
  existing files. Timestomping is a technique that modifies the timestamps of a file
  (the modify, access, create, and change times), often to mimic files that are in
  the same folder. Threat Actor Association: WatchDog Atomics T1070.006 Test #1 Atomics
  T1070.006 Test #2 Atomics T1070.006 Test #3 Atomics T1070.006 Test #4 Atomics T1070.006
  Test #5 Atomics T1070.006 Test #6 Atomics T1070.006 Test #7 Atomics T1070.006 Test
  #8'
logic_format: Splunk
logic: ' `get_endpoint_data` `get_endpoint_data_windows` (LastAccessTime OR LastWriteTime
  OR CreationTime OR SetCreationTime OR SetLastAccessTime OR SetLastWriteTime) | regex
  process="(?i)(set|\.)(creation|(last(access|write)))time(\(|\s*=)" | table _time,
  host, user, *process* `group_events("host,process",10s)` | where event_count < 10
  `hec_collect`'
techniques:
- defense-evasion:indicator removal:timestomp
technique_id:
- T1070.006
data_category:
- Process command-line parameters
references:
- https://www.cadosecurity.com/coinstomp-malware-family-targets-asian-cloud-service-providers/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1070.006/T1070.006.md

Stages and Predicates

Stage 1: search

search source="*" source IN ("WinEventLog:Security", "XmlWinEventLog:Security")

Stage 2: regex

regex match(process, "(?i)(set|\.)(creation|(last(access|write)))time(\(|\s*=)")

Stage 3: table

table *process*, _time, host, user

Stage 4: bucket

bucket _time

Stage 5: stats

stats BY host, process, _time

Stage 6: where

where event_count<10

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
event_countlt
  • 10 corpus 2 (splunk 2)
processregex_match
  • "(?i)(set|.)(creation|(last(access|write)))time((|\s*=)"

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
1LastAccessTime
1LastWriteTime
1CreationTime
1SetCreationTime
1SetLastAccessTime
1SetLastWriteTime