WORM_STTKR.A
Trojan:Win32/AgentBypass.gen!G(Microsoft), W32/CodeCcl-based!Maximus(Authentium), Trojan.Win32.Spy(Ikarus)
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: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives as a component bundled with malware/grayware packages.
It modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall.
TECHNICAL DETAILS
Arrival Details
This worm arrives as a component bundled with malware/grayware packages.
Other System Modifications
This worm adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost\
netsvcs
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\VaSecurity
It modifies the following registry entries to disable the Windows Firewall settings:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 1
(Note: The default value data of the said registry entry is 0.)
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port number 1}:TCP = "{port number 1}:TCP:*:Enabled:@xpsp2res.dll,-22002"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port number 2}:UDP = "{port number 2}:UDP:*:Enabled:@xpsp2res.dll,-22002"
Download Routine
This worm connects to the following URL(s) to download its component file(s):
- http://www.{BLOCKED}a.com/images/newinfo.txt
Other Details
This worm connects to the following possibly malicious URL:
- {BLOCKED}.{BLOCKED}.83.115:35105
SOLUTION
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
Restart in Safe Mode
Step 3
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.
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost\netsvcs
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VaSecurity
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\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {port number 1}:TCP = "{port number 1}:TCP:*:Enabled:@xpsp2res.dll,-22002"
- {port number 1}:TCP = "{port number 1}:TCP:*:Enabled:@xpsp2res.dll,-22002"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {port number 2}:UDP = "{port number 2}:UDP:*:Enabled:@xpsp2res.dll,-22002"
- {port number 2}:UDP = "{port number 2}:UDP:*:Enabled:@xpsp2res.dll,-22002"
Step 5
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\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- From: EnableFirewall = 1
To: EnableFirewall = 0
- From: EnableFirewall = 1
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_STTKR.A. 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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