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BKDR_VAWTRAK.YZH

June 10, 2014
 Analysis by: RonJay Kristoffer Caragay
 ALIASES:

Trojan-PSW.Win32.Tepfer.tzvn(Kaspersky), PWS:Win32/Delf.EM(Microsoft), W32/Tepfer.CCTI!tr.pws(Fortinet), Win32/PSW.Papras.DC 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:

285,849 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

27 May 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.

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
{malware filename} = "regsvr32.exe "{malware path and filename}.dll""

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{GUID 1}
#cert = "31"

HKEY_CLASSES_ROOT\CLSID\{GUID 2}
{GUID 3} = "{hex values}"

HKEY_CLASSES_ROOT\CLSID\{GUID 2}
{GUID 4} = "{hex values}"

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 2}
{GUID 4} = "{hex values}"

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 2}
{GUID 3} = "{hex values}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
TabProcGrowth = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
2500 = "3"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.233.38
  • {BLOCKED}.{BLOCKED}.233.80
  • {BLOCKED}.{BLOCKED}.192.106
  • {BLOCKED}.{BLOCKED}.192.110
  • {BLOCKED}.{BLOCKED}.51.216
  • {BLOCKED}.{BLOCKED}.184.239
  • {BLOCKED}ag.com
  • {BLOCKED}ka.com
  • {BLOCKED}ng.com
  • {BLOCKED}lon.com
  • {BLOCKED}rda.com
  • {BLOCKED}z.com
  • {BLOCKED}on.com
  • {BLOCKED}lpane.com
  • {BLOCKED}ka.com

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.822.02

FIRST VSAPI PATTERN DATE:

27 May 2014

VSAPI OPR PATTERN File:

10.823.00

VSAPI OPR PATTERN Date:

27 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

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
    • {malware filename} = "regsvr32.exe "{malware path and filename}.dll""
  • In HKEY_CLASSES_ROOT\CLSID\{GUID 1}
    • #cert = "31"
  • In HKEY_CLASSES_ROOT\CLSID\{GUID 2}
    • {GUID 3} = "{hex values}"
  • In HKEY_CLASSES_ROOT\CLSID\{GUID 2}
    • {GUID 4} = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{GUID 2}
    • {GUID 3} = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{GUID 2}
    • {GUID 4} = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • NoProtectedModeBanner = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • TabProcGrowth = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 2500 = "3"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = "0"

Step 4

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