BKDR_PCCLIENT.XJ

October 08, 2012
 Analysis by: Christopher Daniel So
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

35,536 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

02 Sep 2010

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\whqezllj
Type = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\whqezllj
Start = 3

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\whqezllj
ErrorControl = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\whqezllj
ImagePath = "\??\%System%\drivers\whqezllj.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\whqezllj
DisplayName = "whqezllj"

Download Routine

As of this writing, the said sites are inaccessible.

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://eads.lucky.{BLOCKED}u.com/index.asp?503000020001
  • http://eadssystem.{BLOCKED}eip.net/index.asp?503000020001

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as BKDR_PCCLIENT.XJ

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • whqezllj

Step 5

Search and delete the file detected as BKDR_PCCLIENT.XJ

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_PCCLIENT.XJ. 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.


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