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Baselines and Anomalies: TryHackMe CTF Writeup / walkthrough

Task 1 - Introduction

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Q1. Let's begin.

No Answer Needed

Task 2 - Baselining Hardware Inventory

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  1. Download the given file , It would be a xlsx file with similar name of Asset-Inventory-with-Anomalies-1733034688169.xlsx
  2. Open the file in any xlsx viewer. Data within the file looks like following :
    xlsx file content

Q1. What is the name of the workstation that has the anomalous IP address?

Lets find the anomalous ip address of the workstation in above file.

  • Look at carefully at the files, the entry no 16 have different ip which somehow doesnot matches anyone of that workstations ip address. br
    xlsx entry

Answer šŸ‘‰ WS-LON-004


Q2. What is the name of the server with the anomalous IP address?

  • Similarly look at the ip address of servers that looks different.
  • Look at entry no 8 , which have different ip
    xlsx entry

Answer šŸ‘‰ SVR-NYC-BKUP01


Q3. Which workstation has a device model different from the rest?

  • Now this time look at the device model of each workstations
  • You can easily find the different device model with your sharp eyes
    xlsx entry

Answer šŸ‘‰ WS-NYC-004

Task 3 - Baselining Software Inventory

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Q1. There are two installed software programs that should not be included in Anna's list. Which ones are they? Share their serial numbers. Answer format: X, Y

  • Think like a detective, which software should not be there.
  • Althogh software looks trusted , but ... why are there multiple software with the same service and having much less workstations !!
    anna's software list

Answer šŸ‘‰ 9, 15

Task 4 - Living Off the Land

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Q1. When trying to identify if an activity was performed by the administrator or not, what is the biggest tool that a defender can use?

admin activity

Answer šŸ‘‰ communication


Q2. Which process can be used to track and approve changes to the firewall Access Control List?

Change Management and Approvals

Answer šŸ‘‰ Change Management and Approvals

Task 5 - Baselining Network Traffic

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Q1. If we are looking for DNS traffic bypassing the local DNS server, what should we exclude from the search of all queries to the DNS port?

internal dns server

Answer šŸ‘‰ Internal DNS server

Task 6 - Baselining Identity and Access Management

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Q1. What kind of alert should be generated if a user logs in from two vastly geographically different places in a short amount of time?

impossible travel

Answer šŸ‘‰ Impossible travel

Task 7 - Identifying Suspicious Environment Specific Use Cases

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  • Start the machine and wait for 5 minutes
  • Visit the given url ()
  • Click on 3 line on top left then click on discover
    menu button
  • Make sure that sorted is selected
    elastic discover kibana

Q1. You have been alerted of a login outside of normal office hours on the 27th of July, 2024. Can you identify the time this login happened?

  • Now we know that a login alert occure on 27th July 2024,outside of normal office hours
  • Change the time from 26th July 2024 to 28th July 2024
    search time update
  • We know that this event occure outside of normal of office hours, which can be possibly to early in morning or late night
  • Lets analyze the first events of the day , there are 8 events. Click on the event
    narrow down the events
  • From Available fields click on plus(+) icon of description , domain, hardware_info_ip
    adding fields
  • Now we can easily find the answer of each question by just looking at the dashboard.
    updated dshboard

Answer šŸ‘‰ 06:37:07.659259000


Q2. Which user logged in at this time?

Answer šŸ‘‰ Mia Perez


Q3. This user performed anomalous activities from two different machines; what is the IP address of the other machine?

Answer šŸ‘‰ 192.168.1.36


Q4. What suspicious domain does this user connect to?

Answer šŸ‘‰ c2server.com

Task 8 - Conclusion

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Q1. I am ready to hunt for anomalies.

No Answer Needed