Analysis by: Rika Joi Gregorio
ALIASES:

Trojan:Win32/AgentBypass.gen!G(Microsoft), W32/CodeCcl-based!Maximus(Authentium), Trojan.Win32.Spy(Ikarus)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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

Tamaño del archivo 100,731 bytes
Tipo de archivo DLL
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 26 Mar 2013

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

Motor de exploración mínimo 9.300
Primer archivo de patrones de VSAPI 9.818.05
Primera fecha de publicación de patrones de VSAPI 26 Mar 2013
Versión de patrones OPR de VSAPI 9.819.00
Fecha de publicación de patrones OPR de VSAPI 27 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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

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

[ Learn More ]

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"
  • 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"

Step 5

Restore this modified registry value

[ Learn More ]

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

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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