BKDR_VAWTRAK.YUH

 Analysis by: Al Victor de Leon

 ALIASES:

Backdoor:Win32/Vawtrak.F (Microsoft), Trojan-Dropper.Win32.Dapato.edqb (Kaspersky), Trojan-Spy.Zbot (Ikarus), W32/Papras.DE!tr.pws (Fortinet)

 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: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This backdoor 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:

420,864 bytes

File Type:

EXE

Initial Samples Received Date:

03 Jul 2014

Arrival Details

This backdoor 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 backdoor 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}\{malware filename}.{malware extension name}""

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{CLSID 1}

HKEY_CLASSES_ROOT\CLSID\{CLSID 2}

HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 1}

HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 2}

It adds the following registry entries:

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_CLASSES_ROOT\CLSID\{CLSID 1}
#cert = "{hex value}"

HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 1}
#cert = "{hex value}"

HKEY_CLASSES_ROOT\CLSID\{CLSID 2}
{CLSID 3} = "{hex value}"

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