The following analytic identifies when the attacker tool Certify is used through an in-memory PowerShell function to enumerate Active Directory Certificate Services (AD CS) environments. The default command line arguments for the binary version of this tools are similar to PowerShell calls and perform near identical enumeration or exploitation functions.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-06-25
- Author: Steven Dick
- ID: f533ca6c-9440-4686-80cb-7f294c07812a
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 7 8 `powershell` EventCode=4104 (ScriptBlockText IN ("*find *") AND ScriptBlockText IN ("* /vulnerable*","* -vulnerable*","* /enrolleeSuppliesSubject *","* /json /outfile*")) OR (ScriptBlockText IN (,"*auth *","*req *",) AND ScriptBlockText IN ("* -ca *","* -username *","* -u *")) OR (ScriptBlockText IN ("*request *","*download *") AND ScriptBlockText IN ("* /ca:*")) | stats count min(_time) as firstTime max(_time) as lastTime list(ScriptBlockText) as command Values(OpCode) as reason values(Path) as file_name values(UserID) as user by _time Computer EventCode | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | eval file_name = case(isnotnull(file_name),file_name,true(),"unknown") | eval signature = substr(command,0,256) | rename Computer as dest,EventCode as signature_id | `detect_certify_with_powershell_script_block_logging_filter`
The SPL above uses the following Macros:
detect_certify_with_powershell_script_block_logging_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
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/220.127.116.11/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell..
Known False Positives
Unknown, partial script block matches.
Associated Analytic Story
|90.0||100||90||Certify arguments through PowerShell detected on $dest$.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1