Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This spyware attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

It checks for the presence of the following processes which are related to Outpost Personal Firewall and ZoneLabs Firewall Client. It terminates if either of the said processes exist. This is to ensure that it runs uninterrupted.

  TECHNICAL DETAILS

File Size: 122,368 bytes
Memory Resident: Yes
Initial Samples Received Date: 23 Aug 2010

Installation

This spyware drops copies of itself in the Windows system folder and appends garbage code to the dropped copy to avoid easy detection. The dropped copies uses the following file names:

  • sdra64.exe

It then creates the following non-malicious file(s):

  • %system%\lowsec\user.ds - used to save the gathered information
  • %system%\lowsec\local.ds - copy of the encrypted downloaded file

It creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:

  • %system%\lowsec

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

  • _AVIRA_2108
  • _AVIRA_2109

It injects itself into the following processes as part of its memory residency routine:

  • Winlogon.exe
  • Svchost.exe

Autostart Technique

This spyware modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = %System%\userinit.exe, %System%\sdra64.exe,

(Note: The default value data of the said registry entry is %System%\Userinit.exe.)

Other System Modifications

This spyware also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Network
UID = {computer name}_{random numbers}

Information Theft

This spyware attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.

It accesses the following site to download its configuration file:

  • http://{BLOCKED}z.com/bla/cf.bin

Note that the contents of the file, hence the list of websites to monitor, may change any time.

Stolen Information

The stolen information is saved in the following file:

  • %system%\lowsec\user.ds

Other Details

This spyware did not exhibit propagation routines during testing.

It checks for the presence of the following processes, which are related to Outpost Personal Firewall and ZoneLabs Firewall Client:

  • outpost.exe
  • zlclient.exe

It did not exhibit backdoor routines during testing.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 07.402.12
VSAPI PATTERN Date: 23 Aug 2010
VSAPI PATTERN Date: 8/23/2010 12:00:00 AM

Step 1

Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.PLL

Step 2

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 3

Identify and delete files detected as TSPY_ZBOT.PLL using the Recovery Console

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Network
    • UID={computer name}_{random numbers}

Step 5

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit=%System%\userinit.exe, %System%\sdra64.exe,
      To: %System%\Userinit.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.PLL. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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