Modified by: RonJay Kristoffer Caragay
ALIASES:

TrojanDownloader:Win32/Kuluoz (Microsoft); Packed-AM!4523F3CBAEE0 (McAfee); Trojan-Downloader.Win32.Dofoil.anqi (Kaspersky); Mal/Zbot-PA (Sophos); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan horse Downloader.Generic13.CETX (AVG)

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size: 100,864 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 06 Jun 2014

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 copies of itself into the affected system:

  • %AppDataLocal%\{random 1}.exe

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

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%AppDataLocal%\{random 1}.exe "

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{random 1}

HKEY_CURRENT_USER\Software\{random 2}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\{random 1}
{random} = "{hex values}"

HKEY_CURRENT_USER\Software\{random 2}
{random} = "{hex values}"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\UpdateFlashPlayer_{random}.exe
  • %User Temp%\{random}.bat
  • %AppDataLocal%\{random characters}.exe

(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.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.77.15
  • {BLOCKED}.253.253
  • {BLOCKED}56.232
  • {BLOCKED}32.24

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.828.02
FIRST VSAPI PATTERN DATE: 30 May 2014
VSAPI OPR PATTERN File: 10.829.00
VSAPI OPR PATTERN Date: 30 May 2014

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

Restart in Safe Mode

[ Learn More ]

Step 3

Search and delete these files

[ Learn More ]
There may be some 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%\UpdateFlashPlayer_{random}.exe
  • %User Temp%\{random}.bat
  • %AppDataLocal%\{random characters}.exe

Step 4

Delete this registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random} = "%AppDataLocal%\{random 1}.exe "
  • In HKEY_CURRENT_USER\Software\{random 1}
    • {random} = "{hex values}"
  • In HKEY_CURRENT_USER\Software\{random 2}
    • {random} = "{hex values}"

Step 5

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_CURRENT_USER\Software
    • {random 1}
  • In HKEY_CURRENT_USER\Software
    • {random 2}

Step 6

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