Modified by: Rhena Inocencio
ALIASES:

TrojanDownloader:Win32/Karagany.I (Microsoft), Downloader-CUU.gen.q (McAfee)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

It does not have any backdoor routine.

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

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size: 19,456 bytes
File Type: EXE
File Compression: UPX
Memory Resident: Yes
Initial Samples Received Date: 05 Oct 2012
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

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

  • yUo9Ck1Io

It injects codes into the following process(es):

  • explorer.exe

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}i.com/752458.html

It saves the files it downloads using the following names:

  • %User Temp%\~!#{random value}.tmp

(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.)

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

Information Theft

This Trojan does not have any information-stealing capability.

NOTES:

It executes the downloaded file using the following command:

  • regsvr32 -s %User Temp%\~!#{random value}.tmp

As of this writing, the said site is accessible but the server does not return anything.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.442.07
FIRST VSAPI PATTERN DATE: 05 Oct 2012
VSAPI OPR PATTERN File: 9.443.00
VSAPI OPR PATTERN Date: 06 Oct 2012

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 TROJ_DLOADR.KSG

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete the file detected as TROJ_DLOADR.KSG

[ 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 5

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.
  • %User Temp%\~!#{random value}.tmp

Step 6

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