Analysis by: Joseph Obed
 Modified by: Kathleen Notario
ALIASES:

Trojan:Win32/Korlia.B (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

This Trojan may be dropped by other malware.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 5,120 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 24 Feb 2012
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_ARTIEF.XPL

Installation

This Trojan injects codes into the following process(es):

  • IExplore.exe

Autostart Technique

This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\dns.exe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}1.{BLOCKED}0.202.198/jp/soft2.rar

It saves the files it downloads using the following names:

  • %Windows%\tasks\conime.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

NOTES:

It connects to the following URL to inform a remote malicious user of its installation:

  • http://{BLOCKED}.{BLOCKED}.202.198/jp/news2.asp?id={random}host:{hostname}user:{username}OS:{OS}vm:{vm}proxy:{proxy}

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.798.08
FIRST VSAPI PATTERN DATE: 24 Feb 2012
VSAPI OPR PATTERN File: 8.799.00
VSAPI OPR PATTERN Date: 24 Feb 2012

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

Remove the malware/grayware file that dropped/downloaded TROJ_DLOAD.XPL

    • TROJ_ARTIEF.XPL

Step 3

Scan your computer with your Trend Micro product and note files detected as TROJ_DLOAD.XPL

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete files detected as TROJ_DLOAD.XPL

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

Step 6

Search and delete this file

[ 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.
  •  %Windows%\tasks\conime.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOAD.XPL. 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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