Analysis by: RonJay Kristoffer Caragay
ALIASES:

W32/Reveton.AJ!tr(Fortinet), Ransom:Win32/Reveton.Y(Microsoft), Trojan-Ransom.Win32.Foreign.kxgk(Kaspersky), Win32/Reveton.AJ trojan(NOD32)

 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: 90,624 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 23 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 files:

  • %All Users Profile%\Application Data\RUNDLL32.EXE-{random}.txt

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

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%\explorer.lnk

(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.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Multimedia\DrawDib
vga.drv 1276x849x32(BGR 0) = "31,31,31,31"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ACID = "U000015"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\winmgmt\Parameters
ServiceDll = "%All Users Profile%\Application Data\{random}\{malware name}"

(Note: The default value data of the said registry entry is "%System%\wbem\WMIsvs.dll" .)

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.882.03
FIRST VSAPI PATTERN DATE: 24 Jun 2014
VSAPI OPR PATTERN File: 10.883.00
VSAPI OPR PATTERN Date: 24 Jun 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 normal mode and scan your computer with your Trend Micro product for files detected as TROJ_REVETON.YZV. 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.

Step 3

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\Multimedia\DrawDib
    • vga.drv 1276x849x32(BGR 0) = "31,31,31,31"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • ACID = "U000015"

Step 4

Restore this modified 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_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\winmgmt\Parameters
    • From: ServiceDll = "%All Users Profile%\Application Data\{random}\{malware name}"
      To: ServiceDll = "%System%\wbem\WMIsvs.dll"

Step 5

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 Startup%\explorer.lnk
  • %All Users Profile%\Application Data\RUNDLL32.EXE-{random}.txt

Step 6

Restart in Safe Mode

[ Learn More ]


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