TSPY_ZBOT.DHL
PWS:Win32/Zbot.gen!Y (Microsoft), Generic BackDoor.wr (McAfee), Trojan-Dropper.Win32.Injector.bvqf (Kaspersky)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Spyware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This spyware arrives as attachment to mass-mailed email messages.
It does not have any propagation routine.
It does not have any backdoor routine.
It modifies the Internet Explorer Zone Settings.
As of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This spyware arrives as attachment to mass-mailed email messages.
Installation
This spyware drops the following copies of itself into the affected system:
- %Application Data%\{random folder 1}\{random file name 1}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It drops the following files:
- %Application Data%\{random folder 2}\{random file name 2}.{random extension name}
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %Application Data%\{random folder 1}
- %Application Data%\{random folder 2}
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Global\{random GUID}
Autostart Technique
This spyware adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random GUID} = "%Application Data%\{random folder 1}\{random file name 1}.exe"
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
{random key}
Propagation
This spyware does not have any propagation routine.
Backdoor Routine
This spyware does not have any backdoor routine.
Web Browser Home Page and Search Page Modification
This spyware modifies the Internet Explorer Zone Settings.
Download Routine
This spyware connects to the following URL(s) to download its configuration file:
- http://{BLOCKED}age.ru/april.php
As of this writing, the said sites are inaccessible.
NOTES:
This spyware may monitor several finance-related institutions depending on the contents of the configuration file. The configuration file also contains the "drop zone" where it sends stolen information, URL where the configuration file can be downloaded, codes for web inject, and monitored URLs.
Other Details
It does not have rootkit capabilities.
It does not exploit any vulnerability.
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
Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.DHL
Step 3
Restart in Safe Mode
Step 4
Delete this registry key
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_CURRENT_USER\Software\Microsoft
- {random key}
- {random key}
Step 5
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random GUID} = "%Application Data%\{random folder 1}\{random file name 1}.exe"
- {random GUID} = "%Application Data%\{random folder 1}\{random file name 1}.exe"
Step 6
Search and delete these folders
- %Application Data%\{random folder 1}
- %Application Data%\{random folder 2}
Step 7
Reset Internet security settings
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.DHL. 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.
NOTES:
The created registry key HKEY_CURRENT_USER\Software\Microsoft\{random key} cannot be identified by the users since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup if the users have one. Note that the key, {random key} need not to be deleted since it won't cause the user system any harm.
In deleting the created folders, please take note of the malware path of the file(s) detected earlier.
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