Threat Descriptions

Trojan.Agent.Formbook

Classification

Category :

Malware

Type :

Trojan

Platform :

W32

Aliases :

Trojan.Agent.Formbook

Summary

Trojan.Agent.Formbook monitors activity on the Firefox web browser in order to steal login details for the Facebook social media network.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Note: Description is based on analysis of sample (SHA1) 524e1011c26b6bf7e23f5d107222397129f9893d.

In addition to stealing login details, Trojan.Agent.Formbook can also:

  • Capture screenshots,
  • Delete user cookies,
  • Try to connect to google.com to confirm Internet connectivity,
  • Contact a remote site (its C&C server) to download and install other files,
  • Forward any stolen data to the C&C server,
  • Disable the Task Manager,
  • And shut down and restart the computer.

Distribution

The trojan is spread as a specially-crafted document file attached to spam email messages. If the user opens the attached file, the trojan is launched.

Evading detection

Trojan.Agent.Formbook checks the computer for any common anti-debugging techniques or keywords, such as "VM", "Sandbox", ââ,¬Å""VMWare Users.exe", and "VMWare Service". If any are found, the trojan immediately exits.

This step is intended to make it harder for security researchers to analyze the malware.

Registry changes

The trojan adds the following registry key to the Windows registry so that it will automatically run whenever the computer is started:

  • HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run\WindowsUpdate
    C:\Users\user\AppData\Local\Temp\cne\axo.exe
    C:\Users\user\AppData\Local\Temp\cne\pwm-axa

Files dropped

Trojan.Agent.Formbook drops multiple script files with random extensions in a folder named CNE in the Temp folder, with most being decoys to camouflage its actual usable components. Examples of some of the files it drops are:

  • C:\Users\user\AppData\Local\Temp\cne\pwm-axa
  • C:\Users\user\AppData\Local\Temp\cne\CDWDY
  • C:\Users\user\AppData\Local\Temp\cne\sni.mp3
  • C:\Users\user\AppData\Local\Temp\cne\axo.exe
  • C:\Users\user\AppData\Local\Temp\cne\grw.bmp
  • C:\Users\user\AppData\Local\Temp\cne\fif.ico
  • C:\Users\user\AppData\Local\Temp\cne\mba.icm
  • C:\Users\user\AppData\Local\Temp\cne\wvj.dat
  • C:\Users\user\AppData\Local\Temp\cne\rfv.bmp
  • C:\Users\user\AppData\Local\Temp\cne\wnc.mp3
  • C:\Users\user\AppData\Local\Temp\cne\eri.pdf

Scripts run

The trojan uses the following command to run the pwm-axa script file:

  • C:\Users\user\AppData\Local\Temp\cne\axo.exe pwm-axa

It then runs another script file, this one with a random name. As an example, the script file CDWDY is run next using the following argument:

  • C:\Users\user\AppData\Local\Temp\cne\axo.exe CDWDY

This script launches a new thread and injects it into the explorer.exe process by using the following sequence of command prompts:

  • "/c copy "%TEMP%\RegSvcs.exe"
  • "%PROGRAMFILES%\colorcpl79b.bat" /V
  • "/c del "%TEMP%\RegSvcs.exe

From there, the trojan can begin monitoring the Firefox browser for activity.

Password stealing

If the user opens Facebook's login page in the Firefox browser, Trojan.Agent.Formbook steals any data the user enters into the login form on the page. The stolen data is then forwarded to the trojan's C&C server.

Network activity

The trojan attempts to connect to the following remote servers:

  • www[.]clicks-track[.]info/list/hx28/Su
  • maxsutton[.]co[.]uk
  • solderie[.]dream3w[.]com
  • lifekeeper[.]com[.]au
  • brinematriscript[.]com
  • jaimagroup[.]com
  • sdvernoms[.]ml
  • tny[.]im/9TK
  • tny[.]im/9Uw
  • tny[.]im/9G1
  • tny[.]im/9Q6
  • tny[.]im/9H1
  • tny[.]im/9R7
  • tny[.]im/9Tc
  • tny[.]im/9RM
  • tny[.]im/9G0
  • tny[.]im/9Oq
  • tny[.]im/9Oh