splunk-security_content/docs/_posts/2021-11-12-windows_installutil_credential_theft.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Windows InstallUtil Credential Theft	InstallUtil, Signed Binary Proxy Execution	Endpoint	2021-11-12	true		InstallUtil Defense Evasion Signed Binary Proxy Execution Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

The following analytic identifies the Windows InstallUtil.exe binary loading vaultcli.dll and Samlib.dll. This technique may be used to execute code to bypassing application control and capture credentials by utilizing a tool like MimiKatz. \ When InstallUtil.exeis used in a malicous manner, the path to an executable on the filesystem is typically specified. Take note of the parent process. In a suspicious instance, this will be spawned from a non-standard process likeCmd.exe, PowerShell.exeorExplorer.exe`.
If used by a developer, typically this will be found with multiple command-line switches/arguments and spawn from Visual Studio.
During triage review resulting network connections, file modifications, and parallel processes. Capture any artifacts and review further.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-11-12
• Author: Michael Haag, Splunk
• ID: ccfeddec-43ec-11ec-b494-acde48001122

ATT&CK

ID	Technique	Tactic
T1218.004	InstallUtil	Defense Evasion

| T1218 | Signed Binary Proxy Execution | Defense Evasion |

Search

`sysmon` EventCode=7  process_name=installutil.exe ImageLoaded IN ("*\\samlib.dll", "*\\vaultcli.dll") 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer, process_name, ImageLoaded, OriginalFileName, process_id 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_installutil_credential_theft_filter`

Associated Analytic Story

• Signed Binary Proxy Execution InstallUtil

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and module loads from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

Kill Chain Phase

• Exploitation
• Privilege Escalation

Known False Positives

Typically this will not trigger as by it's very nature InstallUtil does not need credentials. Filter as needed.

RBA

Risk Score	Impact	Confidence	Message
80.0	80	100	An instance of parent_process_name spawning process_name was identified on endpoint dest by user user loading samlib.dll and vaultcli.dll to potentially capture credentials in memory.

Reference

• https://gist.github.com/xorrior/bbac3919ca2aef8d924bdf3b16cce3d0

Test Dataset

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.004/atomic_red_team/windows-sysmon.log

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