Analysis by: Mark Joseph Manahan
ALIASES:

TrojanDownloader:Win32/Cbeplay.P (Microsoft), Backdoor.Win32.ZAccess.bafj (Kasperksy), a variant of Win32/Kryptik.ARVZ trojan (Eset)

 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: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: 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 connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 127,752 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Jan 2013
Payload: Displays graphics/image, Collects system information

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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Update = "{Malware Path and Filename}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Update = "{Malware Path and Filename}"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
tKRGi7Gas = "{Hex Values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
Gs8FR8 = "{Hex Values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
HnYb3KZ8 = "{Hex Values}"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot

Other Details

This Trojan connects to the following URL(s) to get the affected system's IP address:

  • http://www.ip-address.org/ip-checker.php

It connects to the following website to send and receive information:

  • {BLOCKED}.{BLOCKED}.86.137/ndex.php

NOTES:

It gathers the following information for its ransomware routine:

  • Malware Version & Subid
  • OS Version
  • System Default Language ID
  • System Metrics(Desktop Width and Height)
  • Ip Address,Location and ISP

Using this information, it locks the screen (disabling taskmgr.exe and explorer.exe) then display a ransomware threat.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.648.09
FIRST VSAPI PATTERN DATE: 11 Jan 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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • Update = "{Malware Path and Filename}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Update = "{Malware Path and Filename}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • tKRGi7Gas = "{Hex Values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • Gs8FR8 = "{Hex Values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • HnYb3KZ8 = "{Hex Values}"

Step 4

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

NOTES:

If the system cannot restart in Safe mode due to deleted registries, a damaged cleanup template is necessary for automatic cleanup and recovery.


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