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TROJ_AGENT.AUVV

October 08, 2012
 Analysis by: Karl Dominguez
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes


  TECHNICAL DETAILS

File Size:

131,072 bytes

File Type:

PE

Memory Resident:

Yes

Payload:

Creates files, Connects to URLs/Ips, Drops files

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\3361\svchost.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It creates the following folders:

  • %System%\3361

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
svchost.exe = %System%\3361\svchost.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
svchost.exe = %System%\3361\svchost.exe

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Use FormSuggest = yes

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableScriptDebuggerIE = yes

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Error Dlg Displayed On Every Error = no

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Use FormSuggest = yes

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\Main
DisableScriptDebuggerIE = yes

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\Main
Error Dlg Displayed On Every Error = no

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\Main
Use FormSuggest = yes

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\3361\svchost.exe = %System%\3361\svchost.exe:*:Enabled:SVCHOST.EXE

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}z.{BLOCKED}9.net/new.html
  • http://{BLOCKED}k.{BLOCKED}9.net/PushMission2Client03.asp?MAC=&Publicer=kk_01

  SOLUTION

Minimum Scan Engine:

8.900

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

Identify and terminate files detected as TROJ_AGENT.AUVV

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  %System%\3361

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Use FormSuggest = yes
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • DisableScriptDebuggerIE = yes
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Error Dlg Displayed On Every Error = no
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • Use FormSuggest = yes
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main
    • DisableScriptDebuggerIE = yes
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main
    • Error Dlg Displayed On Every Error = no
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Main
    • Use FormSuggest = yes
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\3361\svchost.exe = %System%\3361\svchost.exe:*:Enabled:SVCHOST.EXE"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • svchost.exe = %System%\3361\svchost.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • svchost.exe = %System%\3361\svchost.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT.AUVV. 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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