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BKDR_AGENT.NCM

October 25, 2012
 ALIASES:

Backdoor:Win32/Agent.NH (Microsoft); [00002060.EXE]:Generic.eh !! (McAfee); Trojan.Panddos (Symantec); Backdoor.Win32.Agent.ezr (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

18,432 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

25 Oct 2012

Arrival Details

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

  • %System%\{malware file name}.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.)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
IEAK

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\TransactionService
Description = "¶àÓû§Ö§³Ö·þÎñ£¬Ìṩ¶àÏ̳߳ÌÐòÔËÐС£"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Connection Wizard
ShellNext = "http://www.{BLOCKED}oft.com/isapi/redir.dll?prd=ie&clcid=0x0409&pver=6.0&ar=home"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Connection Wizard
Completed = "{random values}"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\CA\Certificates\
8B24CD8D8B58C6DA72ACE097C7B1E3CEA4DC3DC6
Blob = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This backdoor drops the following files:

  • %System%\mssvc32.dll
  • %Temp%\ieFBB5.tmp

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

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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_CURRENT_USER\Software\Microsoft
    • IEAK

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\SYSTEM\ControlSet001\Services\TransactionService
    • Description = "¶àÓû§Ö§³Ö·þÎñ£¬Ìṩ¶àÏ̳߳ÌÐòÔËÐС£"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Connection Wizard
    • ShellNext = "http://www.{BLOCKED}oft.com/isapi/redir.dll?prd=ie&clcid=0x0409&pver=6.0&ar=home"

Step 4

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_CURRENT_USER\Software\Microsoft\Internet Connection Wizard
    • From: Completed = "{random values}"
      To: Completed = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\CA\Certificates\8B24CD8D8B58C6DA72ACE097C7B1E3CEA4DC3DC6
    • From: Blob = "{random values}"
      To: Blob = ""{random values}""

Step 5

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.
  • %System%\mssvc32.dll
  • %Temp%\ieFBB5.tmp

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_AGENT.NCM. 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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