I-Worm.Tetton
Details
I-Worm.Tettona
This is the worm virus spreading via the Internet being attached to infected emails. The worm also has backdoor routine.
The worm itself is Windows PE EXE file about 35Kb of length (compressed by Petite, decompressed size – about 75Kb), written in Microsoft Visual C++.
The texts and attached file names in infected messages are different, they depend on current date and Italian language support:
Subjects are:
Incredible.. Incredibile.. Urgente! (vedi allegato) Qualsiasi cosa fai,falla al meglio.
The message body begins with “Hello,” or “Ciao,” text, then Bodies are:
see this interesting file.
okkio all’allegato 
devi assolutamente vedere il file che ti ho allegato.
apri subito l’allegato,e’ MOLTO interessante.
The message body is completed with “A prestoall” or “Bye.” text.
Attached files:
tettona.exe
euro.exe
tattoo.exe
The worm activates from infected email only in case a user clicks on attached file. The worm then installs itself to the system, runs spreading routine and backdoor.
Installing
While installing the worm copies itself to Windows directory with the DLLMGR32.EXE name and registers that file in system registry auto-run key:
HKLM\Software\Microsoft\Windows\CurrentVersion\Run DllManager = %windir%\dllmgr32.exe
The worm then displays fake error message:
Error
VBRUN49.DLL not found!
Spreading
To send infected messages the worm uses direct connection to default SMTP server, then opens WAB database (Windows Address Book) and sends messages to all addresses found in there.
Backdoor
The backdoor procedure opens connection on port 5001 and listens to the “master”. Then it processes following instructions:
“HELO” – replies with “Hello, guy” text
“SCAN” – scans all directories and reports dir/files in there (like remote DIR command)
“EXEC” – runs specified file
“UNINST” – removes itself from the system, including registry “Run” key.
“VIEW” – displays to “master” specified file
“DOWN” – downloads to “master” specified file
Payload
On January 12th the worm displays the message:
Hello,
Ciao,
il tuo computer É infettato dal virus FralÍ.
Certo che devi essere proprio un pirlone,
per esserti fatto fregare dal mio stupidissimo worm.
Va bÉ,vÁ,non ti preoccupare,oggi non sono in vena di cattiverie,
ed É anche un giorno festivo per me.
Buona giornata..
by 4nt4R35
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