Email-Worm:W32/Sober.N
Summary
Sober.N email worm was found on 19th of April, 2005. It sends itself as an attachment in email messages with English or German texts.
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
The worm is written in Visual Basic. The worm's file is a modified UPX packed PE executable about 73 kilobytes long.
The worm sends different types of email messages with English and German texts and an attachment. The attachment is a ZIP archive containing the worm's executable.
The worm composes messages with subject lines such as "I've_got your EMail on my_account!" and "FwD: Ich bin's nochmal" with attachments such as your_text.zip.
Installation to system
When the worm's file is started it opens text editor with the following text as a decoy:
When the worm's file is run, it copies itself as "services.exe" into the %WinDir%\Config\system\ folder, created by the worm.
Sober.N worm adds startup keys for "services.exe" in System Registry:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "SystemCheck" = "%WinDir%\Config\system\services.exe" [HKCU\Software\Microsoft\Windows\CurrentVersion\Run] "_SystemCheck" = "%WinDir%\Config\system\services.exe"
The worm also creates the following files to installation folder:
zipped.wrm maddys.xyz
'zipped.wrm' contains base64-encoded worm, used in spreading. 'maddsys.xyz' is used to store email addresses.
The worm also writes the following files to system folder:
nonrunso.ber langeinf.lin adcmmmmq.hjg xcvfpokd.tqa
These files are used to deactivate previous variants of the worm.
Spreading in emails
The worm sends different types of email messages with English and German texts and its file attached. The attachment is a ZIP archive containing the worm's executable.
Before spreading the worm scans files with certain extensions on all hard disks to harvest email addresses. Files with the following extensions are scanned:
pmr phtm stm slk inbox imb csv bak imh xhtml imm imh cms nws vcf ctl dhtm cgi pp ppt msg jsp oft vbs uin ldb abc pst cfg mdw mbx mdx mda adp nab fdb vap dsp ade sln dsw mde frm bas adr cls ini ldif log mdb xml wsh tbb abx abd adb pl rtf mmf doc ods nch xls nsf txt wab eml hlp mht nfo php asp shtml dbx
The worm ignores email addresses that contain any of the following substrings:
@www @from. smtp- @smtp. ftp. .dial. .ppp. anyone @gmetref sql. someone nothing you@ user@ reciver@ somebody secure whatever@ whoever@ anywhere yourname mustermann@ mailer-daemon variabel noreply -dav law2 .qmail@ freeav @ca. abuse winrar domain. host. viren bitdefender spybot detection ewido. emsisoft linux @foo. winzip @example. bellcore. @arin @iana @avp icrosoft. @sophos @panda @kaspers free-av antivir virus verizon. @ikarus. @nai. @messagelab nlpmail01. clock
The worm composes emails with both English and German texts. If the worm sends infected messages to domains with suffixes '.de', '.ch', '.at', '.li' and also to 'gmx.' domain, it composes messages in German, otherwise English messages are composed.
The worm composes the following messages:
Subjects:
I've_got your EMail on my_account! FwD: Ich bin's nochmal
Body texts:
Hello, First, Very Sorry for my bad English. Someone is sending your private emails on my address. It's probably an email provider error! At time, I've got over 10 mails on my account, but the recipient are you. I have copied all the mail text in the windows text-editor for you & zipped then. Make sure, that this mails don't come in my mail-box again. bye Verdammt,,,, ich hatte vergessen Dir meinen Text mitzuschicken. Aber bitte nicht woanders darueber Reden, ich wuerde mich dann zu Tode blamieren! Ich melde mich. Bis bald ;)
Attachments:
your_text.zip Private-Texte.zip
The actual worm executable name inside the attachement is 'mail.document.Datex-packed.exe'.