WORM_NITOL.BI

October 11, 2012
 Analysis by: Nikko Tamana
 ALIASES:

W32/QQhelper.C.gen!Eldorado (FProt), Backdoor.Win32.Inject (Ikarus), DDoS:Win32/Nitol.B (Microsoft), a variant of Win32/ServStart.AD trojan (NOD32), Backdoor.Nitol (Norton), Trojan.Win32.Redosdru.C (v) (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

45,741 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

08 Oct 2012

Arrival Details

This worm 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 worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\6to4
ImagePath = %SystemRoot%\System32\svchost.exe -k netsvcs

It adds and runs the following services:

  • netsvcs_{random value}

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\6to4\Parameters
ServiceDll = "%System%\{random filename}.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\6to4\Parameters
ServiceMain = "StartRouter"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\6to4\Security
Security = "{random numbers}"

Other Details

This worm sets the attributes of the following file(s) to Hidden and System:

  • %System%\lpk.dll
  • %System%\dllcache\lpk.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It deletes itself after execution.

NOTES:

This worm drops a copy of itself in all folders in all physical drives containing an executable (.EXE) file, It uses the file name LPK.DLL for its dropped copy.

It changes the file attributes of the original LPK.DLLfound in Windows system and %System%\dllcache folders to Read-only, hidden, and system.

This worm accesses the non-malicious site cidr.odn.ne.jp.