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BOOT_XPAJ.SM

December 05, 2012
 Analysis by: Rhena Inocencio
 ALIASES:

Trojan:DOS/Xpaj.B (Microsoft)

 PLATFORM:

DOS

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  TECHNICAL DETAILS

File Size:

Varies

File Type:

DOS

Initial Samples Received Date:

29 Nov 2012

Arrival Details

This malware arrives via the following means:

  • PE_XPAJ infection

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • avp.exe
  • avgnt.exe
  • avguard.exe
  • sched.exe
  • avastui.exe
  • ccsvchst.exe
  • avgcsrvx.exe
  • avgnsx.exe
  • avgrsx.exe
  • avgtray.exe
  • avgwdsvc.exe
  • egui.exe

Other Details

This Trojan does the following:

  • automatically loads PE_XPAJ.C-O every time the system boots
  • terminates several AV processes
  • injects code to browser to download encrypted files

NOTES:

This is Trend Micro's detection for Master Boot Records (MBR) which have been modified by PE_XPAJ malware family.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.558.04

FIRST VSAPI PATTERN DATE:

29 Nov 2012

VSAPI OPR PATTERN File:

9.559.00

VSAPI OPR PATTERN Date:

30 Nov 2012

Restore your system's Master Boot Record (MBR)

To restore your system's Master Boot Record (MBR):

• On Windows XP and Server 2003:

  1. Insert your Windows Installation CD into your CD drive then restart your computer.
  2. When prompted, press any key to boot from the CD.
  3. On the Main Menu, type r to enter the Recovery Console.
  4. Type the number that corresponds to the drive and folder that contains Windows (usually C:\WINDOWS) and press Enter.
  5. Type your Administrator password and press Enter.
  6. In the input box, type the following then press Enter:
    fixmbr {affected drive}
  7. Type exit and press Enter to restart the system normally.

• On Windows Vista and 7:

  1. Insert your Windows Installation DVD into the DVD drive, then press the restart button on your computer.
  2. When prompted, press any key to boot from the DVD.
  3. Depending on your Windows Installation DVD, you might be required to choose the installation language. On the Install Windows window, choose your language, locale, and keyboard layout or input method. Click Repair your computer.
  4. Select Use recovery tools that can help fix problems starting Windows. Select your installation of Windows. Click Next.
  5. If the Startup Repair window appears, click Cancel, Yes, then Finish.
  6. In the System Recovery Options menu, click Command Prompt.
  7. In the Command Prompt window, type the following then press Enter:
    BootRec.exe /fixmbr
  8. Type exit and press Enter to close the Command Prompt window.
  9. Click Restart to restart your computer normally.

NOTES:

Trend Micro Rescue Disk scans and cleans systems infected with XPAJ variants. For further instructions on how to use this tool, you may refer to the Rescue Disk Instruction Page.


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