ID | Technique | Tactic |
---|---|---|
T1003.002 | Security Account Manager | Credential Access |
T1003 | OS Credential Dumping | Credential Access |
Detection: Detect Copy of ShadowCopy with Script Block Logging
Description
The following analytic detects the use of PowerShell commands to copy the SAM, SYSTEM, or SECURITY hives, which are critical for credential theft. It leverages PowerShell Script Block Logging (EventCode=4104) to capture and analyze the full command executed. This activity is significant as it indicates an attempt to exfiltrate sensitive registry hives for offline password cracking. If confirmed malicious, this could lead to unauthorized access to credentials, enabling further compromise of the system and potential lateral movement within the network.
Search
1`powershell` EventCode=4104 ScriptBlockText IN ("*copy*","*[System.IO.File]::Copy*") AND ScriptBlockText IN ("*System32\\config\\SAM*", "*System32\\config\\SYSTEM*","*System32\\config\\SECURITY*")
2| stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText
3| rename Computer as dest
4| rename UserID as user
5| `security_content_ctime(firstTime)`
6| `security_content_ctime(lastTime)`
7| `detect_copy_of_shadowcopy_with_script_block_logging_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Powershell Script Block Logging 4104 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational' |
Macros Used
Name | Value |
---|---|
powershell | (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational") |
detect_copy_of_shadowcopy_with_script_block_logging_filter | search * |
detect_copy_of_shadowcopy_with_script_block_logging_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Known False Positives
Limited false positives as the scope is limited to SAM, SYSTEM and SECURITY hives.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
PowerShell was identified running a script to capture the SAM hive on endpoint $dest$ by user $user$. | 80 | 80 | 100 |
References
-
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934
-
https://github.com/JumpsecLabs/Guidance-Advice/tree/main/SAM_Permissions
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
XmlWinEventLog |
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
Source: GitHub | Version: 4