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TROJ_AGENT.AVDD

October 13, 2012
 ALIASES:

Trojan:Win32/VB.VK (Microsoft); Generic.dx!bdq4 (McAfee); PAK:ASPack, Trojan.Win32.Agent2.cntc (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Clicker.Delf.KH (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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 modifies files, disabling programs and applications from properly running.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

91,648 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

11 Jul 2012

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.

Other System Modifications

This Trojan modifies the following files:

  • %Start Menu%\Programs\Internet Explorer.LNK

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

It deletes the following files:

  • %Start Menu%\Programs\Internet Explorer.lnk

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

It adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}

HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\
DefaultIcon

HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\
Shell\ÊôÐÔ(&D)\Command

HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\
Shell\Open(&O)\Command

HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\
ShellFolder

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Desktop\NameSpace\{DF98EB15-3044-6340-85B4-F6931B3A61A0}

HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}

HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\
DefaultIcon

HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\
Shell\ÊôÐÔ(&D)\Command

HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\
Shell\Open(&O)\Command

HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\
ShellFolder

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Desktop\NameSpace\{64570DE9-2184-C242-B068-665F5D400B13}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\ShellFolder
Attributes = "a"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\ShellFolder
Attributes = "a"

Dropping Routine

This Trojan drops the following files:

  • %Windows%\regedit.ico
  • %Windows%\TAEKMAN.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

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

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.

  • In HKEY_CLASSES_ROOT\CLSID
    • {DF98EB15-3044-6340-85B4-F6931B3A61A0}
  • In HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\Shell\ÊôÐÔ(&D)
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\Shell\Open(&O)
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}
    • ShellFolder
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Desktop\NameSpace
    • {DF98EB15-3044-6340-85B4-F6931B3A61A0}
  • In HKEY_CLASSES_ROOT\CLSID
    • {64570DE9-2184-C242-B068-665F5D400B13}
  • In HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\Shell\ÊôÐÔ(&D)
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\Shell\Open(&O)
    • Command
  • In HKEY_CLASSES_ROOT\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}
    • ShellFolder
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Desktop\NameSpace
    • {64570DE9-2184-C242-B068-665F5D400B13}

Step 3

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\SOFTWARE\Classes\CLSID\{DF98EB15-3044-6340-85B4-F6931B3A61A0}\ShellFolder
    • Attributes = "a"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{64570DE9-2184-C242-B068-665F5D400B13}\ShellFolder
    • Attributes = "a"

Step 4

Search and delete these files

[ Learn More ]
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.
  • %Windows%\regedit.ico
  • %Windows%\TAEKMAN.exe

Step 5

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

Step 6

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %Start Menu%\Programs\Internet Explorer.LNK

Step 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Start Menu%\Programs\Internet Explorer.lnk


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