BKDR_FAKEMS.SV

 Analysis by: Rhena Inocencio

 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:

  • 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.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

164,352 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Feb 2013

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 registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
ServiceDll = "%System%\{random file name}.dll"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
DataVersion = "{port value}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
DataVersionEx = "{encrypted pass value}"

Dropping Routine

This backdoor drops the following files:

  • %System%\{random file name}.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

NOTES:
This backdoor accepts the following parameters:

  • install /port:{user-defined} /pass:{user-defined} /svc:{user-defined}