F-Secure Virus Descriptions : Bagle

 [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\d3dupdate.exe]

or

terminate the running 'bbeagle.exe' process with Task Manager

2, Delete the worm from the Windows System Directory:

 %SysDir%\bbeagle.exe

Detailed Description

System Infection

Upon execution Bagle copies itself to the Windows System Directory with the filename 'bbeagle.exe'. This file is added to the registry as

[HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\d3dupdate.exe]

to ensure that the worm will be activated when Windows starts.

To indicate whether the worm was run for the first time it creates another value in the registry as

 [HKCU\Software\Windows98\frun]

When started the first time the worm starts the Windows Calculator (calc.exe) to conceal its presence.

Email Propagation

Bagle recursively searches all drives on the infected computer to locate Windows Address Book (WAB) files, text and HTML. It parses these files and collects all email addresses it can find.

Files with the following extensions are checked:

 .WAB
 .TXT
 .HTM
 .HTML

Using its own SMTP engine Bagle sends messages with infected attachments to the collected addresses. The SMTP engine uses direct Mail eXchange (MX) lookup on the target domain so it does not depend on email settings of the infected computer.

The emails Bagle sends have the following characteristics:

 Subject: Hi
 Body:    Test =)
          <random characters>

          --
          Test, yep.

 Attachment: <random characters>.exe

The mailer routine will ignore all the addresses that contain the any of these strings:

 .r1
 @hotmail.com
 @msn.com
 @microsoft
 @avp.

Payload

Bagel contains a backdoor that listens on a TCP port 6777 which is hardcoded in the worm's body. This backdoor component provides remote access to the infected computer. It can be used to download and execute arbitrary programs from the Internet.

When the worm is started it connects to a list of predefined web servers and tries to access a PHP file with certain parameters. One of the parameters is the TCP port where the backdoor is listening which suggests that this functionality is used to collect the addresses of infected computers.

Bagle has reportedly tried to download the Mitglieder trojan to some infected computers.

More information on Mitglieder trojan is available here:

http://www.f-secure.com/v-descs/mitglied.shtml

Remote Removal

F-Secure can confirm that the remote removal method found by Joe Stewart of Lurhq does indeed work.

Sending a specific byte sequence to port 6777 on the infected computers causes the worm to delete itself from the System Directory and terminate its process. The registry values are not removed but since the file does not exist Windows will ignore those.

The byte sequence to be sent:

 0x43 0xff 0xff 0xff 0x00 0x00 0x00 0x00 0x04 0x31 0x32 0x00

Please note that the usage of this method agains someone else's computers might be legally questionable.

Bagle Structure.

The following picture briefly shows the structure of the Bagle worm, which can be appreciated in full detail in the PDF graph available from:

http://www.f-secure.com/virus-info/v-pics/bagle-a.pdf

Spreading Statistics

The following table shows the country distribution of the infections. On each column the number indicates the percentage over the total number of infected machines, and the 2 letter code indicates the country or geographical area where the infected computers have been located.

        15.30% CN             1.03% CZ
        12.53% KR             1.00% NO
        11.39% US             0.93% IL
        11.06% AU             0.91% CA
        5.97% DE              0.87% PL
        5.19% FR              0.79% -- (Unknown location)
        3.33% JP              0.71% SE
        3.01% HK              0.66% ID
        2.35% GB              0.59% LT
        2.14% EU              0.56% RU
        2.08% IN              0.56% CH
        1.92% TW              0.54% AT
        1.90% DK              0.48% NZ
        1.69% MY              0.45% PH
        1.37% ES              0.44% BR
        1.20% TH              0.44% FI
        1.15% TR              0.40% SG
        1.05% IT              0.35% BE

 Note 1: The table only displays the first 36 entries.
 Note 2: The data used when creating the table only contains
 infected computers up to the 19th of January, 2004 at  17:26 GMT+1

The following graph shows the increase in activity created by the worm from 19th of January at 00:00 (GMT+1) up to the same day at 17:15 (GMT+1). The red line indicates the total number of hits received by a given web server. The green line shows the increase in number of infected machines, starting from around 300 and growing near 80.000 unique machines by the end of the monitoring period shown in the graph.

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Detection

F-Secure Anti-Virus detects Bagle worm with the update published on January 19th, 2004

[FSAV_Database_Version]

Version=2004-01-19_01

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Description: Katrin Tocheva, January 18th, 2004;

Technical Details: Gergely Erdelyi & Ero Carrera, January 19th, 2004;

F-Secure Corporation