BKDR_CYBERG.A

April 24, 2015
 Analysis by: Jennifer Gumban
 ALIASES:

Found Luhe.Fiha.A (AVG)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • 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

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.

Installation

This backdoor drops the following files:

  • %Application Data%\{random values}\ak.tmp
  • %Application Data%\{os}v3.4.2.2.vbs
  • %System%\wbem\Logs\wbemprox.log
  • %TEMP%\{4 characters}_appcompat.txt
  • %TEMP%\{os}

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %System%\Acrobat\svchost.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

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\Policies\
Explorer\Run
Policies = "%System%\Acrobat\svchost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Antvirus = "%System%\Acrobat\svchost.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Realtek(Audio) = "%System%\Acrobat\svchost.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Policies = "%System%\Acrobat\svchost.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\!@#$%¨¨&*VISUAL!@#$%¨¨&*
FirstExecution = "{date executed} -- {time executed}"

HKEY_CURRENT_USER\Software\!@#$%¨¨&*VISUAL!@#$%¨¨&*
NewIdentification = "!@#$%¨¨&*VISUAL!@#$%¨¨&*"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{UID}
StubPath = "%System%\Acrobat\svchost.exe"

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}cdt.no-ip.org
  • {BLOCKED}conda32.no-ip.org
  • {BLOCKED}alhocdt.no-ip.org