computers

Hack The Box Sherlocks: CrownJewel2

Trevor Steen

Sep 5, 2024 • 3 min read

If you have not yet set up an environment for viewing logs, I suggest you check out my writeup on that process.

I needed to use most of the hints on this one because I have not worked in a Windows domain environment for a while, but it was fun to dive back in.

First download, extract, and upload the necessary files for this challenge.

Task 1

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When utilizing ntdsutil.exe to dump NTDS on disk, it simultaneously employs the Microsoft Shadow Copy Service. What is the most recent timestamp at which this service entered the running state, signifying the possible initiation of the NTDS dumping process?

Windows Event ID 7036 is service start and stops. So a quick query for that revealed many events – about 100 various services, but narrowing this down by searching those services for "Shadow" pointed me in the right direction.

Narrowed down to the Shadow Copy Service

In the image above we can see one event of interest to us and the timestamp 2024-05-15T05:39:55.705Zthat is the answer to this challenge. Keep in mind the format and that you need to Zulu/UTC time. If you copy the time from the GUI row extracted value, you will get local time.

Task 2

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Identify the full path of the dumped NTDS file.

Using the plumbing of a Velociraptor query I was able to craft my own query in Security Onion to find the events of interest.

winlog.event_id:(216 OR 327 OR 326 OR 325) AND winlog.channel:Application AND "ntds.dit"

This resulted in a handful of events of which, only one seemed like it could reasonably be the event in question with a path of C:\\Windows\\Temp\\dump_tmp\\Active Directory\\ntds.dit

Task 3

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When was the database dump created on the disk?

Simply get the Timestamp from the event above

2024-05-15 05:39:56

Task 4

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When was the newly dumped database considered complete and ready for use?

https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-038a

The middle of the article above defines some of the related events for an NTDS dump. Event 327 indicates the copy is complete. Only 2 events with this ID are returned both with the same timestamp.

Task 5

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Event logs use event sources to track events coming from different sources. Which event source provides database status data like creation and detachment?

This is just more review of the logs we have been looking at. Specifically the Provider value, which is ESENT for the last few Tasks.

Task 6

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When ntdsutil.exe is used to dump the database, it enumerates certain user groups to validate the privileges of the account being used. Which two groups are enumerated by the ntdsutil.exe process? Also, find the Logon ID so we can easily track the malicious session in our hunt.

Based on the hint, Event 4799 is what we are looking for. This query groups the events by the Target ID, so we know which groups are enumerated. The individual log events include the Logon ID.

winlog.event_id:4799 AND winlog.event_data.CallerProcessName:*ntdsutil.exe | groupby winlog.event_data.TargetUserName

Task 7

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Now you are tasked to find the Login Time for the malicious Session. Using the Logon ID, find the Time when the user logon session started.

Using the hint, it was easy enough to filter on the indicated log event IDs.

winlog.event_id:("4768" OR "4769" OR "5379")