Detection rules › Splunk
Exchange New Export Request (PowerShell)
This use case looks for exchange cmdlet to output email into a pst file. Adversaries may use these commands in order to exfiltrate sensitive information. - Threat Group Association: APT, 29, APT31, CL-STA-0043
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Collection | T1114.001 Email Collection: Local Email Collection, T1114.002 Email Collection: Remote Email Collection |
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: '5694.5956'
title: Exchange New Export Request
description: 'This use case looks for exchange cmdlet to output email into a pst file.
Adversaries may use these commands in order to exfiltrate sensitive information.
- Threat Group Association: APT, 29, APT31, CL-STA-0043 - Software Association:
ALPHV/BlackCat, Conti, Hafnium, Qakbot/Qbot, SEABORGIUM'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4104) OR
TERM(EventCode=4103)) TERM(New-MailboxExportRequest) | regex process="(?i)-FilePath.{1,}\.pst"
| table _time, host, user signature_id, process, process_* `group_events("host",1s)` '
techniques:
- collection:email collection:local email collection
- collection:email collection:remote email collection
technique_id:
- T1114.002
- T1114.001
data_category:
- PowerShell logs
- Process command-line parameters
references:
- https://www.volexity.com/blog/2020/12/14/dark-halo-leverages-solarwinds-compromise-to-breach-organizations/
Stages and Predicates
Stage 1: search
search EventCode=4103 EventCode=4104 source="*" source IN ("WinEventLog:Microsoft-Windows-PowerShell/Operational", "WinEventLog:Windows", "XmlWinEventLog:Microsoft-Windows-PowerShell/Operational")
Stage 2: regex
regex match(process, "(?i)-FilePath.{1,}\.pst")
Stage 3: table
table _time, host, process, process_*, signature_id, user
Stage 4: bucket
bucket _time
Stage 5: stats
stats BY host, _time
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 | TERM |
| 1 | "New-MailboxExportRequest" |