BKDR_NUKESPED.E

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 executes then deletes itself afterward.

It executes commands from a remote malicious user, effectively compromising the affected system.

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:

• %User Temp%\Microsoft.Win32.TaskScheduler.dll -> component for SetTaskPathDl
• %User Temp%\drmanidd32.dll ->also detected as BKDR_NUKESPED.E
• %Application Data%\Adobe\Update\SecuUpdates.dll -> renamed copy of drmanidd32.dll

(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.. %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.)

It drops and executes the following files:

• %User Temp%\end.bat -> used to delete itself and the malware
• %User Temp%\start.bat -> used to execute and delete components
• %User Temp%\SetTaskPathDl.exe ->used to rename and create a scheduled task for drmanidd32.dll

(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 executes then deletes itself afterward.

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

• 74tw9401-719s-85hk-op16-562ge02bm369

Other System Modifications

This Backdoor deletes the following files:

• %User Temp%\end.bat
• %User Temp%\start.bat
• %User Temp%\SetTaskPathDl.exe
• %User Temp%\Microsoft.Win32.TaskScheduler.dll
• %User Temp%\drmanidd32.dll

(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.)

Backdoor Routine

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

• go -> Ok signal for the backdoor capability
• ti -> Change Sleep time multiplier
• sh -> Has same template as fs and ts but has not implemented any function after resolving the host address
• fs -> Send and Receive Backdoor Commands via UDT Library (UDT::socket, UDT::connect, etc)
  Has the following subcommands:
  • _dir Send a directory listing for path specified
  • _exe Execute arbitrary shell commands via WinExec
  • _get Encrypt and upload arbitrary file
  • _got Encrypt and upload arbitrary file then delete file
  • _put Download, Decrypt and save arbitrary file
  • _quit Exit “fs” backdoor command loop
• ts -> Send and Receive Backdoor Commands via common APIs (socket, bind, connect, etc)
  Has the following subcommands:
  • _dir Send a directory listing for path specified
  • _del Delete arbitray file
  • _exe Execute arbitrary shell commands via WinExec
  • _get Encrypt and upload arbitrary file
  • _got Encrypt and upload arbitrary file then delete file
  • _put Download, Decrypt and save arbitrary file
  • _dll Inject a DLL into a process via remote thread
  • _dlu Unload DLL
  • _cap Save screenshot to file and send to C&C, then delete
  • _inf Gather info to a temp file and Send to C&C, then delete:
    • Operating system version
    • Username
    • Computer name
    • System drive
    • Local time
    • All connected drives and properties
    • Network adapter properties
    • Disk free space
    • All installed programs
  • _cmd Execute comspec with arbitrary parameter and send results to C&C
  • _prc Send a full running process list to C&C
  • _quit Exit backdoor command thread
• dl -> DLL Injection via CreateRemoteThread
• du -> DLL Unloading via FreeLibrary
• de -> Secure Delete File Function, renames multiple times then delete
• cm -> Execute ComSpec with Arbitrary Parameters
• cu -> Send sytem info through the DNS query
• ex -> Execute Arbitrary Shell Commands

Other Details

This Backdoor does the following:

• Tries to resolve a specific C2 DNS name by querying a CNAME on the following URLs:
  • {BLOCKED}.{BLOCKED}ttp.com
  • {BLOCKED}.{BLOCKED}.tm
  • {BLOCKED}o.{BLOCKED}.net
  
  However, the CNAME “pYjr6YpmK-lKJ2YLB0csBgYGqMbnxmfmSeaG.e.r“, was not resolved during the analysis.

It adds the following scheduled tasks:

• • Task Name: Adobe Update Checker
  • Schedule: At log on of User
  • Task to be Run: rundll32.exe %appdata%\Adobe\Update\SecuUpdates.dll,start now