TSPY_ZBOT.ERZ
VirTool:Win32/Obfuscator.AAS (Microsoft)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Spyware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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 modifies the Internet Explorer Zone Settings.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
340,992 bytes
EXE
Yes
28 Aug 2012
Connects to URLs/IPs
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.
Installation
This spyware drops the following copies of itself into the affected system and executes them:
- %User Profile%\Application Data\{random folder}\{random file name 1}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It drops the following component file(s):
- %Application Data%\{random file name 2}.{random extension}
(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:
- %User Profile%\Application Data\{random folder}
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
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
{GUID} = "%User Profile%\Application Data\{random folder}\{random file name 1}.exe"
Other System Modifications
This spyware adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Privacy
CleanCookies = "0"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
25800:UDP = "25800:UDP:*:Enabled:UDP 25800"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
23226:TCP = "23226:TCP:*:Enabled:TCP 23226"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
Web Browser Home Page and Search Page Modification
This spyware modifies the Internet Explorer Zone Settings.
Stolen Information
This spyware sends the gathered information via HTTP POST to the following URL:
- http://{pseudorandom domain name}.info
- http://{pseudorandom domain name}.com
- http://{pseudorandom domain name}.biz
- http://{pseudorandom domain name}.net
- http://{pseudorandom domain name}.org
Other Details
This spyware connects to the following URL(s) to check for an Internet connection:
- http://www.google.com
- http://www.bing.com
It deletes the initially executed copy of itself
NOTES:
The configuration file may contain URLs where it downloads an updated copy of itself and where it sends its gathered information.
SOLUTION
9.200
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.ERZ
Step 3
Restart in Safe Mode
Step 4
Reset Internet security settings
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\Internet Explorer\Privacy
- CleanCookies = "0"
- CleanCookies = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {GUID} = "%User Profile%\Application Data\{random folder}\{random file name 1}.exe"
- {GUID} = "%User Profile%\Application Data\{random folder}\{random file name 1}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- 25800:UDP = "25800:UDP:*:Enabled:UDP 25800"
- 25800:UDP = "25800:UDP:*:Enabled:UDP 25800"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- 23226:TCP = "23226:TCP:*:Enabled:TCP 23226"
- 23226:TCP = "23226:TCP:*:Enabled:TCP 23226"
Step 6
Search and delete this file
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
- %Application Data%\{random file name 2}.{random extension}
Step 7
Search and delete these folders
- %User Profile%\Application Data\{random folder}
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.ERZ. 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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