BKDR_PRESHIN.AB


 ALIASES:

TrojanProxy:Win32/Preshin.B(Microsoft), Win32/TrojanProxy.Preshin.B trojan(Eset)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This backdoor may be dropped by other malware. It arrives as a component bundled with malware/grayware packages.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

As of this writing, the said sites are inaccessible.

It steals certain information from the system and/or the user.

  TECHNICAL DETAILS

File Size:

114,176 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

27 Mar 2013

Payload:

Steals information, Compromises system security, Downloads files

Arrival Details

This backdoor may be dropped by other malware.

It arrives as a component bundled with malware/grayware packages.

Installation

This backdoor drops the following files:

  • {malware file name}.{malware extension}-KLMP.pf

It adds the following processes:

  • iexplore.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Ultro_ISO_0369

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download File
  • Download and Execute File

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://www.{BLOCKED}p.caedufjf.net/my/logon.php?000932{random characters}

However, as of this writing, the said sites are inaccessible.

Download Routine

This backdoor connects to the following URL(s) to download its component file(s):

  • http://www.{BLOCKED}p.caedufjf.net/my/logon.php?000932{random characters}

It saves the files it downloads using the following names:

  • %User Temp%\iacup.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

As of this writing, the said sites are inaccessible.

Information Theft

This backdoor steals the following information:

  • Host Name
  • Local IP Address
  • OS Version

Stolen Information

This backdoor saves the stolen information in the following file:

  • %User Temp%\wg.dat - will be deleted afterwards

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • www.google.com

NOTES:

For this malware to execute properly, it should be run by any of these processes:

  • rundll32.exe
  • iexplore.exe
  • firefox.exe

This malware also connects to www.google.com to download and save the file as %User Temp%\losivp.tmp and deletes it afterwards.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.820.02

FIRST VSAPI PATTERN DATE:

27 Mar 2013

VSAPI OPR PATTERN File:

9.821.00

VSAPI OPR PATTERN Date:

28 Mar 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product and note files detected as BKDR_PRESHIN.AB

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.  
  • %User Temp%\iacup.dat
  • %User Temp%\losivp.tmp
  • {malware file name}.{malware extension}-KLMP.pf

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PRESHIN.AB. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


Did this description help? Tell us how we did.