TSPY_ZBOT.NSK
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: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It bypasses the Windows firewall. This allows the malware to perform its intended routine without being detected by an installed firewall.
It modifies the Internet Explorer Zone Settings.
TECHNICAL DETAILS
320,000 bytes
EXE
Yes
25 Mar 2013
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system:
- %Application Data%\{random1}\{random}.exe
(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 drops the following component file(s):
- %Application Data%\{random}\{random}.{random extension}
(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}
- %Application Data%\{random1}
(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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%Application Data%\{random1}\{random}.exe"
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random} = "{hex values}"
HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random1} = "{hex values}"
It adds the following registry keys as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
It modifies the following registry entries to disable the Windows Firewall settings:
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 Trojan modifies the Internet Explorer Zone Settings.
Information Theft
This Trojan accesses the following site to download its configuration file:
- http://{BLOCKED}gic.com/office/smart/server/format.bin
SOLUTION
9.300
9.816.05
25 Mar 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
Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.NSK
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_CURRENT_USER\Software\Microsoft
- {random}
- {random}
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
- {GUID} = "%Application Data%\{random1}\{random}.exe"
- {GUID} = "%Application Data%\{random1}\{random}.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"
Step 6
Search and delete these folders
Step 7
Reset Internet security settings
Step 8
Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.NSK. 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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