Analysis by: JasperM


Windows 98, ME, NT, 2000, XP, Server 2003


  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes


However, as of this writing, the said sites are inaccessible.

It connects to a website to send and receive information.


File Size: 65,024 bytes
File Type: PE
Memory Resident: Yes

Arrival Details

However, as of this writing, the said sites are inaccessible.


This backdoor drops and executes the following files:

  • %Application Data%\Microsoft\ALG.exe - also detected as BKDR_PROXY.SMP

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

Autostart Technique

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

ALG = %Application Data%\Microsoft\ALG.exe

Backdoor Routine

This backdoor connects to the following websites to send and receive information:



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

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\Windows\CurrentVersion\Run
    • ALG=%Application Data%\Microsoft\ALG.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as BKDR_PROXY.SMP. 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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