Wurmark.L
Summary
Wurmark.L is an email worm that spreads using several different languages. It also drops a variant of Rbot on the infected system.
Removal
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
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Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
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Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
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Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
Technical Details
Installation to system
When run, the worm drops the following three files from its resource:
bx.exe bszip.dll ANSMTP.DLL
'bx.exe' is a copy of Rbot. 'bszip.dll' and 'ANSMTP.DLL' are used later in email spreading. The work also writes the following files in the Windows system folder:
cmd.com regedit.com taskkill.com tasklist.com tracert.com ping.com netstat.com
The contents of these files are characters 'MZ'. As 'com' extension is evaluated before 'exe' in Windows program execution, this trick tries to disable the execution of above programs with 'exe' extension.
The worm executes 'bx.exe' which installs itself in system. This file is a variant of Rbot. When 'bx.exe' is run, it copies itself as 'winis.exe' in the Windows system directory and adds the following registry keys:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "IE Runtimes" = "%SysDir%\winis.exe"
This ensures that it will be executed at next system startup. The bot can be used as a backdoor, collecting system information, logging keystrokes, relaying spam and for various other purposes.
The worm also opens a jpg-file from predefined URL. The picture looks like this:
email spreading
Wurmark.L gathers email addresses from the MSN messenger and Yahoo IM client contact lists. The worm uses the dropped SMTP component (ANSMTP.DLL) to send infected messages. It can construct the messages in 7 different languages. The language is selected using the locale of the infected computer.
Here are the possible english messages:
Attachment Returned This file was rejected by the recipient You suck! I have enclosed why you suck and your not going to like it :@ My new details Hi i've changed email address if you would like to keep in contact i have enclosed my new details Party Invite!! You have been invited to my party please download the details and tell me if you will be able to make it , Thanks!
Here are the possible german messages:
Zubeh r Ging Diese Akte wurde von der Empf nger zur ckgewiesen Sie saugen! Ich habe umgeben, warum Sie saugen und Ihr Gehen nicht zu wie ihm :@ Meine neuen Details Hallo nderte ive email address, wenn Sie zu m chten Unterhalt im Kontakt habe ich meine neuen Details umgeben Beteiligtes Laden!! Sie sind zu meinem Beteiligten eingeladen worden ddownloaden Sie bitte die Details und erkl ren Sie mir wenn Sie in der LageSIND, es zu bilden, Dank!
Here are the possible french messages:
L'Attachement Est retourn Ce dossier a rejet par le destinataire Vous sucez! J'ai enferm pourquoi vous sucez et votre ne pas aller comme lui :@ Mes nouveaux d tails Bonjour l'ive a chang le email address si vous voudriez subsistance en contact j'ai joint mes nouveaux d tails La Partie Invitent!! Vous avez invit ma partie t chargez svp les d tails et me dites si vous pourrez la faire, merci!
Possible italian messages:
Il Collegamento Ha rinviato Questa lima stata rifiutata dal destinatario Succhiate! Ho accluso perch succhiate e vostro non andare come ad esso :@ I miei nuovi particolari Hi il ive ha cambiato il email address se gradiste a conservazione in contatto ho accluso i miei nuovi particolari Il Partito Invita!! Siete stati invitati al mio partito prego trasferite i particolari dal sistema centrale verso i satelliti e mi dite se potrete farlo, ringraziamenti!
Possible portuguese messages:
O Acess rio Retornou Esta lima foi rejeitada pelo receptor Voc suga! Eu inclu porque voc suga e seu n o lhe ir como :@ Usted aspira! He incluido porqu usted aspira y el su no ir como a l :@ O Partido Convida!! Voc foi convidado a meu partido download por favor os detalhes e diz-me se voc pudesse o fazer, agradecimentos!
Possible spanish messages:
El Accesorio Volvi Este archivo fue rechazado por el recipiente Usted aspira! He incluido porqu usted aspira y el su no ir como a l :@ Mis nuevos detalles Hi el ive cambi email address si usted quisiera a mantener contacto he incluido mis nuevos detalles El Partido Invita!! Le han invitado a mi partido descarga por favor los detalles y me dice si usted puede hacerlo, gracias!
Possible dutch messages:
Het aanhechtsel Keerde Terug Dit bestand werd door de ontvanger afgekeurd U zuigt! Ik heb waarom u zuigt bijgevoegd en uw gaand alsof het niet :@ Mijn nieuwe details Hi veranderde ive email aanspreekt of u van naar zou houden Hou in contact ik heb bijgevoegd mijn nieuwe details bij De partij Uitnodig!! U bent naar mijn partij alstublieft download de details uitgenodigd worden en vertel mij indien u hem zult kunnen maken, Bedankt!
Attachment name is selected from the following list:
Party.pif File.pif Corrupt.pif details.pif Party.scr File.scr Corrupt.scr details.scr
The file is packed inside 'File.zip' which is the actual attachment in the email.