FRISK Software International

Summary of W32/Aplore.A@mm
Alias:Aplore, Aphex, I-Worm.Aphex, Psec
Discovered: 9 Apr 2001
Infection Method:Infected e-mail attachments and IRC
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Brief description
Technical description

Brief Description
Aplore is mass-mailing worm that spreads via Outlook and IRC. The main component is written in Delphi and contains the IRC spreading routines and an embedded web server.

Technical Description
Binary part

When the worm is executed it copies itself to the Windows System Directory as 'explorer.exe'. This copy is linked into the registry to 'HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Explorer' so it will be started when Windows starts up.

The worm has an IRC engine inside and uses it to connect to a public IRC server. It joins random channels and sends private messages to users who join the channel. It offers a web link that points to the infected machine.

The page on the URL says that the user has to download a plugin to view the content.

The page has a REFRESH tag so in one second it offers the worm file for download.

When the user chooses to run the file it starts and infects the system.

Script part

The spreading routine is in a Visual Basic file email.vbs that the worm drops once the attached file is executed. When the Outlook Application is closed by the worm, the script file is deleted.

The email messages that the worm sends look as follows:

        From: infected-user-name
        Subject: .
        Body: .

[Analysis: Katrin Tocheva and Gergely Erdelyi; F-Secure Corp.; April 9th, 2002]

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