Squid Game

Attacker 1

01. What is the malicious C2 domain you found in the maldoc where an executable download was attempted?

We will analyze this document by using oletools.

$ oledump.py attacker1.doc 
  1:       114 '\x01CompObj'
  2:      4096 '\x05DocumentSummaryInformation'
  3:      4096 '\x05SummaryInformation'
  4:     13859 '1Table'
  5:     33430 'Data'
  6:       365 'Macros/PROJECT'
  7:        41 'Macros/PROJECTwm'
  8: M    9852 'Macros/VBA/ThisDocument'
  9:      5460 'Macros/VBA/_VBA_PROJECT'
 10:       513 'Macros/VBA/dir'
 11:       306 'MsoDataStore/ÇYÕXGNÎÕÃUKWÛÎIS2BKÍÐÐ==/Item'
 12:       341 'MsoDataStore/ÇYÕXGNÎÕÃUKWÛÎIS2BKÍÐÐ==/Properties'
 13:      4096 'WordDocument'

You will find obfuscated script from this document. At this stage, we can't do anything.

$ oledump.py -s 8 -v attacker1.doc 
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()
On Error Resume Next
DBvbDlfxWGXm = WifblkBfDS + CBool(2243) + Len(ChrW(5 + 9) + ChrW(3)) + LenB(Trim("QHSiqJpWNfHbmnlvPbbP")) + Len(lZlRjJlQKnBntw)
lQbWzTrJtfhGiaS = pWNDRZbLZdGgl + CBool(5015) + Len(ChrW(1 + 1) + ChrW(2)) + LenB(Trim("XkBMzwHsSZswNPQMBDL")) + Len(SxZnBTiJkRBD)
.......

Try to upload to https://hybrid-analysis.com/arrow-up-right. We will find detail background command from this report https://hybrid-analysis.com/sample/2979b5fbb454e2f13d89e58177f8c1f881bd3f0a0bebb1d27da9e189ba9d284e/618d7f92e234d60f96658a08arrow-up-right.

We will decode this encoded base64.

02. What executable file is the maldoc trying to drop?

03. In what folder is it dropping the malicious executable? (hint: %Folder%)

Try to search GetFolderPath("CommonApplicationData") on google. Here is a link that I found answer - https://stackoverflow.com/questions/895723/environment-getfolderpath-commonapplicationdata-is-still-returning-c-documarrow-up-right

04. Provide the name of the COM object the maldoc is trying to access.

Try to search $clsid = New-Object Guid 'C08AFD90-F2A1-11D1-8455-00A0C91F3880' on google. Here is a link that I found answer - https://strontic.github.io/xcyclopedia/library/clsid_c08afd90-f2a1-11d1-8455-00a0c91f3880.htmlarrow-up-right

05. Include the malicious IP and the php extension found in the maldoc. (Format: IP/name.php)

06. Find the phone number in the maldoc. (Answer format: xxx-xxx-xxxx)

07. Doing some static analysis, provide the type of maldoc this is under the keyword "AutoOpen".

08. Provide the subject for this maldoc. (make sure to remove the extra whitespace)

09. Provide the stream number that contains a macro.

10. Provide the stream number that contains a macro.

11. Provide the name of the stream that contains a macro.

Attacker 2

01. Provide the streams (numbers) that contain macros.

02. Provide the size (bytes) of the compiled code for the second stream that contains a macro.

03. Provide the largest number of bytes found while analyzing the streams.

04. Find the command located in the 'fun' field ( make sure to reverse the string).

05. Provide the first domain found in the maldoc.

06. Provide the second domain found in the maldoc.

07. Provide the name of the first malicious DLL it retrieves from the C2 server.

08. How many DLLs does the maldoc retrieve from the domains?

09. Provide the path of where the malicious DLLs are getting dropped onto?

You can also view using olevba

10. What program is it using to run DLLs?

11. How many seconds does the function in the maldoc sleep for to fully execute the malicious DLLs?

12. Under what stream did the main malicious script use to retrieve DLLs from the C2 domains? (Provide the name of the stream).

Attacker 3

01. Provide the executable name being downloaded.

02. What program is used to run the executable?

03. Provide the malicious URI included in the maldoc that was used to download the binary (without http/https).

04. What folder does the binary gets dropped in?

05. Which stream executes the binary that was downloaded?

Attacker 4

01. Provide the first decoded string found in this maldoc.

First we need to analyze using olevba.

Change Hex Format and then decrypt xor with key.

02. Provide the name of the binary being dropped.

03. Provide the folder where the binary is being dropped to.

04. Provide the name of the second binary.

05. Provide the full URI from which the second binary was downloaded (exclude http/https).

Attacker 5

01. What is the caption you found in the maldoc?

02. What is the XOR decimal value found in the decoded-base64 script?

Firstly, dump with olevba. And then you will see base64 format and decode it. You need to remove . and space. And then again, we get another base64.

03. Provide the C2 IP address of the Cobalt Strike server.

Decrypt again!

04. Provide the full user-agent found.

05. Provide the path value for the Cobalt Strike shellcode.

06. Provide the port number of the Cobalt Strike C2 Server.

07. Provide the first two APIs found.

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