TROJ_DLOADER.ZZXX

March 30, 2013
 Analysis by: Mark Joseph Manahan
 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: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size:

49,152 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Mar 2013

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 drops the following component file(s):

  • %User Temp%\upd{3 random char}.dll
  • %System%\netsvc{3 random char}.dll

(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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Download Routine

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

  • http://police.{BLOCKED}u.com/page.txt

It saves the files it downloads using the following names:

  • %User Temp%\msg.dll - detected as TROJ_AGENT.YOI

(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.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.790.09

FIRST VSAPI PATTERN DATE:

16 Mar 2013

VSAPI OPR PATTERN File:

9.791.00

VSAPI OPR PATTERN Date:

16 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

Remove the malware/grayware file dropped/downloaded by TROJ_DLOADER.ZZXX

     TROJ_AGENT.YOI

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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