Detection rules › Splunk
Native Archive Commands (PowerShell)
An adversary may compress and/or encrypt data that is collected prior to exfiltration. Compressing the data can help to obfuscate the collected data and minimize the amount of data sent over the network
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Collection | T1074.001 Data Staged: Local Data Staging, T1560 Archive Collected Data |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body yaml
id: '5525.5749'
title: Native Archive Commands
description: 'An adversary may compress and/or encrypt data that is collected prior
to exfiltration. Compressing the data can help to obfuscate the collected data and
minimize the amount of data sent over the network. - Threat Actor Association: APT28
(aka.Fancy Bear, Fighting Ursa, Forest Blizzard, Pawn Storm, TA422, STRONTIUM),
APT29/Nobelium/Cozy Bear, APT33, Conti, DarkSide, BlackMatter, FIN7, Karakurt, MuddyWater,
TA428, Volt Typhoon, Witchetty - Software Association: Black Basta, NanoCore, Ransom
Cartel, SquirrelWaffle - Atomics T1074.001 Test#3 Atomics T1560 Test#1 Atomics T1560.001
Test #5 Atomics T1560.001 Test #6 Atomics T1560.001 Test #7 Atomics T1560.001 Test
#8 Atomics T1560.001 Test #9 - #TrendingThreat #Russia #Ukraine'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_powershell` TERM(EventCode=4104) (TERM(Compress-Archive)
OR TERM(tar) OR TERM(makecab) OR TERM(compact.exe) OR TERM(compact) OR (TERM(Compression)
TERM(System) TERM(IO))) | regex process!="(Decompress)" | regex process="(?i)Compress-Archive|tar|makecab|compact|System\.IO\.Compression"
| table _time, host, user signature_id, process, process_* | bin span=1s | stats
values(*) as * by _time, host '
techniques:
- collection:data staged:local data staging
- collection:archive collected data
technique_id:
- T1074.001
- T1560
data_category:
- PowerShell logs
- Process command-line parameters
references:
- https://liberty-shell.com/sec/2019/11/06/living-off-the-land-pt2/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_powershell` TERM(EventCode=4104) (TERM(Compress-Archive) OR TERM(tar) OR TERM(makecab) OR TERM(compact.exe) OR TERM(compact) OR (TERM(Compression) TERM(System) TERM(IO)))
Stage 2: regex
| regex process!="(Decompress)"
Stage 3: regex
| regex process="(?i)Compress-Archive|tar|makecab|compact|System\.IO\.Compression"
Stage 4: table
| table _time, host, user signature_id, process, process_*
Stage 5: bucket
| bin span=1s
Stage 6: stats
| stats values(*) as * by _time, host
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
process | regex_match | "(Decompress)" |
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.
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 | "Compress-Archive" |
| 1 | TERM |
| 1 | tar |
| 1 | TERM |
| 1 | makecab |
| 1 | TERM |
| 1 | compact.exe |
| 1 | TERM |
| 1 | compact |
| 1 | TERM |
| 1 | Compression |
| 1 | TERM |
| 1 | System |
| 1 | TERM |
| 1 | IO |