BKDR_HACKDOOR.BAU

April 17, 2013
 Analysis by: Adrianne Chester Camat
 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: Yes

  • 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

File Size:

49,170 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

29 Mar 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.

Installation

This backdoor drops the following non-malicious files:

  • %Temp%\system.tmp

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

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

  • global\systemtime0
  • global\systemtime2

Autostart Technique

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services
STAC99 =

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://www.{BLOCKED}ac.com