Detection rules › Splunk
Read-Only Attribute Removed - Windows (PowerShell)
This use case detects commands removing read-only attributes from files on Windows systems. This technique is used by threat actors to modify or delete critical system files
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment | T1222.001 File and Directory Permissions Modification: Windows Permissions |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4103 | Payload Context: ContextInfo User Data: UserData. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body yaml
id: '17778.29995'
title: Read-Only Attribute Removed - Windows
description: 'This use case detects commands removing read-only attributes from files
on Windows systems. This technique is used by threat actors to modify or delete
critical system files. Atomics T1222.001 Test #3'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4103) OR
"<EventID>4103<" OR TERM(EventCode=4104) OR "<EventID>4104<") (TERM(attrib) OR TERM(attrib.exe))
"-r" | regex process="(?i)\s+-r\s+" | table _time, host, user parent_*, process,
process_* | bin span=1s | stats values(*) as * by _time, host '
techniques:
- defense-evasion:file and directory permissions modification:windows file and directory
permissions modification
technique_id:
- T1222.001
data_category:
- PowerShell logs
references:
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1222.001/T1222.001.md#atomic-test-3---attrib---remove-read-only-attribute
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4103) OR "<EventID>4103<" OR TERM(EventCode=4104) OR "<EventID>4104<") (TERM(attrib) OR TERM(attrib.exe)) "-r"
Stage 2: regex
| regex process="(?i)\s+-r\s+"
Stage 3: table
| table _time, host, user parent_*, process, process_*
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.
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>4103<" |
| 1 | TERM |
| 1 | "<EventID>4104<" |
| 1 | TERM |
| 1 | attrib |
| 1 | TERM |
| 1 | attrib.exe |
| 1 | "-r" |