BKDR_DASERF.NZU

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.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It deletes the initially executed copy of itself.

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 and executes the following files:

• %User Temp%\sd{random characters}.tmp.bat
• %User Temp%\rr{random characters}.tmp

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\29561
• Global\stpbpuac

It injects codes into the following process(es):

• svchost.exe
• explorer.exe

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Security

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Enum

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
Type = 16

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
ErrorControl = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
ImagePath = "%Program Files%\Common Files\system\reginie.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
DisplayName = "swprv4"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7
Description = "Manages software-based volume shadow copies taken by the Volume Shadow Copy service. If this service is stopped, software-based volume shadow copies cannot be managed. If this service is disabled, any services that explicitly depend on it will fail to start."

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Security
Security = {hex values}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Enum
0 = "Root\LEGACY_SWPRV7\0000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Enum
Count = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\swprv7\Enum
NextInstance = 1

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

• Execute Powershell commands
• Uninstall itself
• Install PlugIn
• Change Activity Time
• Change download URL
• Sleep
• Gather System Information
• Perform Remote Shell
• Create or terminate processes
• Upload, Download, or Execute Files
• Enumerate all drives with corresponding drive types
• Get sha1/md5 of file
• Search, Move, or Delete files
• Get File Information
• Create, Change, or Delete Directory
• Enumerate files and directories

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

• http://www.{BLOCKED}urch.net/geditor/icons/index.php?id0={value}&id1={value}&id2={value}&id3={value}&id6={value}

Dropping Routine

This Backdoor drops the following files:

• %Program Files%\Common Files\System\reginie.exe

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Information Theft

This Backdoor gathers the following data:

• Computer Name
• System Default Language ID
• OS Version
• Is administrator
• Is 64-bit
• Available Disk Space
• User Name

Other Details

This Backdoor deletes the initially executed copy of itself