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Bagle.AY worm

By Mary Landesman, About.com

Jan 26 2005
Bagle.AY is a mass mailing email and P2P filesharing worm with backdoor and downloader capabilites. As with previous variants and most modern email worms, the worm uses its own SMTP engine to spread via email and the From address is spoofed.

Infection impact
When Bagle.AY is executed, it drops a file named sysformat.exe to the Windows system directory and registers that file in the HKCU..\Run key so the worm loads when Windows starts.

Bagle.AY attempts to kill processes associated with various security software found running on infected systems. This could prevent infected users from getting the necessary updates to detect the active infection.

Bagle.AY also deletes registry keys associated with certain Netsky variants.

Bagle.AY opens random ports, contacts the worms author and attempts to download a file from a large number of presumed compromised websites.

Email characteristics
The subject will be any one of the following:

    Delivery service mail
    Delivery by mail
    Registration is accepted
    Is delivered mail
    You are made active

The message body will be one of the following:

    Thanks for use of our software.
    Before use read the help

The attachment will be named one of the following:

    wsd01
    viupd02
    siupd02
    guupd02
    zupd02
    upd02
    Jol03

The file extension will be one of the following:

    COM
    CPL
    EXE
    SCR

P2P characteristics The worm also drops copies of itself to shared folders containing the string 'shar' in its foldername. Filename will be one of the following:

    1.exe
    2.exe
    3.exe
    4.exe
    5.scr
    6.exe
    7.exe
    8.exe
    9.exe
    10.exe
    Ahead Nero 7.exe
    Windown Longhorn Beta Leak.exe
    Opera 8 New!.exe
    XXX hardcore images.exe
    WinAmp 6 New!.exe
    WinAmp 5 Pro Keygen Crack Update.exe
    Adobe Photoshop 9 full.exe
    Matrix 3 Revolution English Subtitles.exe
    ACDSee 9.exe

Removal / Disinfection
Manual removal is not recommended. The infection contains both a remote access and downloader component, thus the system compromise could be extensive. Use updated antivirus software to detect and remove this threat. If an active Bagle.AY infection is discovered, reformatting the compromised system should be considered.

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