TSPY_ZBOT.VUS
PWS:Win32/Zbot (Microsoft), Trojan-Spy.Win32.Zbot.koca (Kaspersky)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Spyware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be dropped by other malware.
It modifies the Internet Explorer Zone Settings.
As of this writing, the said sites are inaccessible.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
382,464 bytes
EXE
Yes
22 Apr 2013
Downloads files
Arrival Details
This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It may be dropped by the following malware:
- TSPY_ZBOT.DL
Installation
This spyware drops the following files:
- %Application Data%\{random letters 1}\{random letters}.exe - copy of itself
- %Application Data%\{random letters 2}\{random letters}.{random letters} - encrypted file
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
It creates the following folders:
- %Application Data%\{random letters 1}
- %Application Data%\{random letters 2}
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Global\{random GUID}
- Local\{random GUID}
It injects itself into the following processes as part of its memory residency routine:
- explorer.exe
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 Characters} = "%Application Data%\{random letters 1}\{random letters}.exe"
Other System Modifications
This spyware adds the following registry keys as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
{random letters}
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://{random 16 characters}.com/{random 8 characters}/{random 9 characters}.php
- such as http://{BLOCKED}ec948fa2bc.com/53085816/0d5e28f7.php
As of this writing, the said sites are inaccessible.
Other Details
This spyware deletes the initially executed copy of itself
NOTES:
It saves a copy of the Windows Address Book as the following:
- %Application Data%\Microsoft\Address Book\{User Name}.wab
- %Application Data%\Microsoft\Address Book\{User Name}.wab~
This spyware may access a remote site to download its configuration file. It 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, the URL where the configuration file can be downloaded, the codes for web injection, and the monitored URLs.
However, it fails to download its configuration file because it is already inaccessible.
SOLUTION
9.200
9.872.05
22 Apr 2013
9.873.00
23 Apr 2013
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Remove malware/grayware files that dropped/downloaded TSPY_ZBOT.VUS
- TSPY_ZBOT.DL
Step 3
Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.VUS
Step 4
Restart in Safe Mode
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 Characters} = "%Application Data%\{random letters 1}\{random letters}.exe"
- {Random Characters} = "%Application Data%\{random letters 1}\{random letters}.exe"
Step 6
Reset Internet security settings
Step 7
Search and delete these folders
- %Application Data%\{random letters 1}
- %Application Data%\{random letters 2}
Step 8
Search and delete these files
- %User Profile%\Application Data\Microsoft\Address Book\{User Name}.wab
- %User Profile%\Application Data\Microsoft\Address Book\{User Name}.wab~
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.VUS. 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.
Step 10
The following created registry key(s) cannot be identified by the user 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 of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:
- HKEY_CURRENT_USER\Software\Microsoft\{random letters}
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