TROJ_ZBOT.BXU
Windows 2000, XP, Server 2003
Threat Type: Spyware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Once users access any of the monitored sites, it starts logging keystrokes. It attempts to steal information, such as user names and passwords, used when logging into certain banking or finance-related websites.
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 terminates if either of the said processes exist. This is to ensure that it runs uninterrupted. It also has rootkit capabilities, which enables it to hide its processes and files from the user.
TECHNICAL DETAILS
Infection Points
This spyware arrives as a file downloaded from the following URLs:
- http://{BLOCKED}www333.com/bot.exe
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 drops the following non-malicious files:
- %System%\lowsec\local.ds
- %System%\lowsec\user.ds
(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 creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:
- %System%\lowsec
(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 injects itself into the following processes as part of its memory residency routine:
- SVCHOST.EXE
- WINLOGON.EXE
Autostart Technique
This spyware modifies the following registry entry(ies) to enable its 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 adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Network
UID = {Computer name}_{Random numbers}
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 0
Information Theft
This spyware accesses the following site to download its configuration file:
- http://{BLOCKED}www333.com/cfg2.bin
Once users access any of the monitored sites, it starts logging keystrokes.
It attempts to access a website to download a file which contains information where the Trojan can download an updated copy of itself, and where to send its stolen data. This configuration file also contains the following list of targeted bank-related websites from which it steals information:
- https://www.gruposantander.es/*
- @*/login.osmp.ru/*
- @*/atl.osmp.ru/*
- https://banking.*.de/cgi/ueberweisung.cgi/*
- https://internetbanking.gad.de/banking/*
- https://www.citibank.de/*/jba/mp#/SubmitRecap.do
Note that the contents of the file, hence the list of websites to monitor, may change any time.
It attempts to steal information from the following banks and/or other financial institutions:
- OSPM
- GAD
- Citibank
Stolen Information
This spyware saves the stolen information in the following file:
- %System%\lowsec\user.ds
(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 sends the gathered information via HTTP POST to the following URL:
- http://{BLOCKED}www333.com/gate.php
Other Details
This spyware checks for the presence of the following processes which are related to Outpost Personal Firewall and ZoneLabs Firewall Client:
- outpost.exe
- zlclient.exe
It terminates if either of the said processes exist. This is to ensure that it runs uninterrupted. It also has rootkit capabilities, which enables it to hide its processes and files from the user.
Variant Information
This spyware has the following MD5 hashes:
- d3eb43240f6e8e08ff97469b7ea2a681
It has the following SHA1 hashes:
- e058ef9fc15cf900a325954f425f006cabf675e4
SOLUTION
Step 1
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 2
Identify and delete files detected as TROJ_ZBOT.BXU using either the Startup Disk or Recovery Console
Step 3
Restore this modified registry value
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: Userinit = %System%\userinit.exe,
Step 4
Delete this registry value
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}
- UID = {Computer name}_{Random numbers}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- EnableFirewall = 0
- EnableFirewall = 0
Step 5
Search and delete this folder
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_ZBOT.BXU. 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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