Password stealer Trojan – Malware Analysis


Hi Visitor, I got this sample of malware shared on VirusBay.

Sample below:

SHA256: 630efa1e2dc642799b867363bb36d1953884480ac29942a1ab20243a8a9620ad

Signature: Microsoft Visual C# v7.0/ Basic .Net and its a Windows forms application.

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Upon execution, this file drops below two files at location C:\Users\<UserProfile>\AppData\Local\Temp\

Dropped files:

C:\Users\<UserProfile>\AppData\Local\Temp\FB_2C02.tmp.exe

C:\Users\<UserProfile>\AppData\Local\Temp\cc3a68ce1dad95ce662e1c51568e3a.exe (Application Server)

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Upon execution of this file, it take a screenshot of current screen and save at C:\Users\<UserProfile>\AppData\Local\Temp location.

Also it adds below file to startup programs.

  • cc3a68ce1dad95ce662e1c51568e3a.exe (Application Server)
  • And main malware sample file.
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FB_2C02.tmp.exe:

SHA256: A02CF7E4D01C3E04C0C6F723A541289A12C5D87ECC47F6B675D84A6B1B0A23B3

File description: Gomorrah

Signature: Microsoft Visual C# v7.0/ Basic .Net and its a Windows forms application.

I used ILSpy decompiler to decompile FB_2C02.tmp.exe. I could see the functions written to achive below purpose.

Purpose:

  1. Steal browser saved user account information.
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I used google chrome on which VM i was doing analysis. I could see this file has created a Passwords.txt file at C:\Users\<UserProfile>\AppData\Local\Temp\Passwords.txt

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Decomplied code of executable which grab google chrome url, username and password.

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2. System Information.

This file also located at C:\Users\<UserProfile>\AppData\Local\Temp

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3. Outlook Password.

This file also located at C:\Users\<UserProfile>\AppData\Local\Temp. As I wasnt using outlook, the file was empty.

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4. Credit Card information

This file CC.txt which stores information about CC also located at C:\Users\<UserProfile>\AppData\Local\Temp.

It was empty too.

Below code grab CC information from the browser.

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Just not from Google chrome but from all below,

  • Amigo
  • Brave
  • Kometa
  • Orbitium
  • Totch
  • Yandex
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It uploads all collected to the remote location. Though I am not able to see it is connecting to remote server anymore because when I ran this, got run time exceptions.

But it gets connected to below URL as its mentioned on VirusTotal detection.

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Summary:

Malware upload below information to remote server.

  • Web account passwords from web browsers.
  • Credit card information from web browser.
  • Outlook passwords.
  • Client machine information.

Thank you.

3 thoughts on “Password stealer Trojan – Malware Analysis

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