Worm/NetSky.AM - Worm

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Summary

Full description

Statistics

Virus:	Worm/NetSky.AM
Date discovered:	28/09/2005
Type:	Worm
In the wild:	No
Reported Infections:	Low
Distribution Potential:	Medium
Damage Potential:	Medium
Static file:	Yes
File size:	33.280 Bytes
MD5 checksum:	0ab51a0826abca7ad25fb3e5797a8f09
VDF version:	6.32.0.49

General Method of propagation:
   • Email

Aliases:
   • Symantec: W32.Mytob.EE@mm
   • Mcafee: W32/Mytob.gen@MM
   • Kaspersky: Net-Worm.Win32.Mytob.cz
   • TrendMicro: WORM_MYTOB.KR
   • Bitdefender: Win32.Mydoom.BA@mm

Platforms / OS:
   • Windows 2000
   • Windows XP

Side effects:
   • Blocks access to security websites
   • Disable security applications
   • Uses its own Email engine
   • Lowers security settings
   • Registry modification
   • Third party control

Files It copies itself to the following location:
• %SYSDIR%\scrigz.exe

It deletes the initially executed copy of itself.

Registry The following registry keys are continuously in an infinite loop added in order to run the processes after reboot.

– [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
• "RAX SYSTEM"="scrigz.exe"

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
• "RAX SYSTEM"="scrigz.exe"

Email It contains an integrated SMTP engine in order to send emails. A direct connection with the destination server will be established. The characteristics are described in the following:

From:
The sender address is spoofed.
Generated addresses. Please do not assume that it was the sender's intention to send this email to you. He might not know about his infection or might not even be infected at all. Furthermore it is possible that you will receive bounced emails telling you that you are infected. This might also not be the case.

To:
– Email addresses found in specific files on the system.
– Email addresses gathered from WAB (Windows Address Book)
– Generated addresses

Subject:
One of the following:
   • *DETECTED* Online User Violation
   • Email Account Suspension
   • Important Notification
   • Members Support
   • Notice of account limitation
   • Security measures
   • Warning Message: Your services near to be closed.
   • You have successfully updated your password
   • Your Account is Suspended
   • Your Account is Suspended For Security Reasons
   • Your new account password is approved
   • Your password has been successfully updated
   • Your password has been updated

Furthermore the subject line could contain random letters.

Body:
The body of the email is one of the following:

   • Dear user %username from receivers email address%,

     It has come to our attention that your %receiver's domain name from email address% User Profile ( x ) records are out of date. For further details see the attached document.

     Thank you for using %receiver's domain name from email address% !
     The %receiver's domain name from email address% Support Team

     +++ Attachment: No Virus (Clean)
     +++ %receiver's domain name from email address% Antivirus - www.%receiver's domain name from email address%

   • Dear user %username from receivers email address%,

     You have successfully updated the password of your %receiver's domain name from email address% account.

     If you did not authorize this change or if you need assistance with your account, please contact %receiver's domain name from email address% customer service at: %sender's email address%

     Thank you for using %receiver's domain name from email address% !
     The %receiver's domain name from email address% Support Team

     +++ Attachment: No Virus (Clean)
     +++ %receiver's domain name from email address% Antivirus - www.%receiver's domain name from email address%

   • Dear %receiver's domain name from email address% Member,

     Your e-mail account was used to send a huge amount of unsolicited spam messages during the recent week. If you could please take 5-10 minutes out of your online experience and confirm the attached document so you will not run into any future problems with the online service.

     If you choose to ignore our request, you leave us no choice but to cancel your membership.

     Virtually yours,
     The %receiver's domain name from email address% Support Team

     +++ Attachment: No Virus found
     +++ %receiver's domain name from email address% Antivirus - www.%receiver's domain name from email address%

   • Dear %receiver's domain name from email address% Member,

     We have temporarily suspended your email account %receiver's email address%.
     This might be due to either of the following reasons:
     1. A recent change in your personal information (i.e. change of address).
     2. Submiting invalid information during the initial sign up process.
     3. An innability to accurately verify your selected option of
     subscription due to an internal error within our processors.
     See the details to reactivate your %receiver's email address% account.

     Sincerely,
     The %receiver's domain name from email address% Support Team

     +++ Attachment: No Virus (Clean)
     +++ %receiver's domain name from email address% Antivirus - www.%receiver's domain name from email address%

Attachment:
The filenames of the attachments is constructed out of the following:

– It starts with one of the following:
   • accepted-password
   • account-details
   • account-info
   • account-password
   • account-report
   • approved-password
   • document
   • email-details
   • email-password
   • important-details
   • new-password
   • password
   • readme
   • updated-password
   • %random character string%

    The file extension is one of the following:
   • zip

The attachment is a copy of the malware itself.

The email looks like the following:

Mailing Search addresses:
It searches the following files for email addresses:
   • adb; asp; cgi; dbx; htm; html; jsp; php; sht; tbb; wab; xml

Address generation for FROM field:
To generate addresses it uses the following strings:
   • admin
   • administrator
   • info
   • mail
   • register
   • service
   • support
   • webmaster

It combines the result with domains that were found in files, which were previously searched for addresses.

Address generation for TO field:
To generate addresses it uses the following strings:
   • adam; alex; andrew; anna; bill; bob; brenda; brent; brian; claudia;
      dan; dave; david; debby; frank; fred; george; helen; jack; james;
      jane; jerry; jim; jimmy; joe; john; jose; josh; julie; kevin; leo;
      linda; maria; mary; matt; michael; mike; paul; peter; ray; robert;
      sales; sam; sandra; serg; smith; stan; steve; ted; tom

It combines the result with domains that were found in files, which were previously searched for addresses.

Avoid addresses:
It does not send emails to addresses containing one of the following strings:
   • .edu; .gov; .mil; abuse; accoun; acketst; anyone; arin.; avp;
      be_loyal:; berkeley; borlan; bsd; bugs; certific; contact; example;
      fcnz; feste; fido; foo.; fsf.; gnu; gold-certs; google; gov.; help;
      hotmail; iana; ibm.com; icrosof; icrosoft; ietf; inpris; isc.o; isi.e;
      kernel; linux; listserv; math; mit.e; mozilla; msn.; mydomai; nobody;
      nodomai; noone; not; nothing; ntivi; page; panda; pgp; postmaster;
      privacy; rating; rfc-ed; ripe.; root; ruslis; samples; secur;
      sendmail; site; soft; somebody; someone; sopho; spm; submit; syma;
      tanford.e; the.bat; unix; usenet; utgers.ed; www; you; your

Prepend MX strings:
In order to get the IP address of the mail server it has the ability to prepend the following strings to the domain name:
   • gate
   • mail
   • mail1
   • mx
   • mx1
   • mxs
   • ns
   • relay
   • smtp

IRC To deliver system information and to provide remote control it connects to the following IRC Server:

Server: rax.**********ihax.info
Port: 43287
Channel: #skyelite
Nickname: [X]%six-digit random character string%

– Furthermore it has the ability to perform actions such as:
    • Download file
    • Execute file
    • Terminate malware
    • Updates itself

Hosts The host file is modified as explained:

– In this case already existing entries remain unmodified.

– Access to the following domains is effectively blocked:
   • avp.com; ca.com; customer.symantec.com; dispatch.mcafee.com;
      download.mcafee.com; ebay.com; f-secure.com; kaspersky.com;
      kaspersky-labs.com; liveupdate.symantec.com;
      liveupdate.symantecliveupdate.com; mast.mcafee.com; mcafee.com;
      microsoft.com; moneybookers.com; my-etrust.com; nai.com;
      networkassociates.com; pandasoftware.com; paypal.com; rads.mcafee.com;
      secure.nai.com; securityresponse.symantec.com; sophos.com;
      symantec.com; trendmicro.com; update.symantec.com;
      updates.symantec.com; us.mcafee.com; viruslist.com; virustotal.com;
      www.amazon.ca; www.amazon.co.uk; www.amazon.com; www.amazon.fr;
      www.avp.com; www.ca.com; www.ebay.com; www.f-secure.com;
      www.grisoft.com; www.kaspersky.com; www.mcafee.com; www.microsoft.com;
      www.moneybookers.com; www.my-etrust.com; www.nai.com;
      www.networkassociates.com; www.pandasoftware.com; www.paypal.com;
      www.sophos.com; www.symantec.com; www.trendmicro.com;
      www.viruslist.com; www.virustotal.com

Process termination List of processes that are terminated:
   • _AVP32.EXE; _AVPCC.EXE; _AVPM.EXE; CMD.EXE; NEC.EXE; TASKMGR.EXE;
      VSHWIN32.EXE; VSISETUP.EXE; VSMAIN.EXE; VSMON.EXE; VSSTAT.EXE;
      VSWIN9XE.EXE; VSWINNTSE.EXE; VSWINPERSE.EXE; W32DSM89.EXE; W9X.EXE;
      WATCHDOG.EXE; WEBDAV.EXE; WEBSCANX.EXE; WEBTRAP.EXE; WFINDV32.EXE;
      WHOSWATCHINGME.EXE; WIMMUN32.EXE; WIN32.EXE; WIN32US.EXE;
      WINACTIVE.EXE; WIN-BUGSFIX.EXE; WINDOW.EXE; WINDOWS.EXE; WININETD.EXE;
      WININIT.EXE; WININITX.EXE; WINLOGIN.EXE; WINMAIN.EXE; WINNET.EXE;
      WINPPR32.EXE; WINRECON.EXE; WINSERVN.EXE; WINSSK32.EXE; WINSTART.EXE;
      WINSTART001.EXE; WINTSK32.EXE; WINUPDATE.EXE; WKUFIND.EXE; WNAD.EXE;
      WNT.EXE; WRADMIN.EXE; WRCTRL.EXE; WSBGATE.EXE; WUPDATER.EXE;
      WUPDT.EXE; WYVERNWORKSFIREWALL.EXE; XPF202EN.EXE; ZAPRO.EXE;
      ZAPSETUP3001.EXE; ZATUTOR.EXE; ZONALM2601.EXE; ZONEALARM.EXE

The following service is disabled:
   • SharedAccess

Miscellaneous It creates the following Mutex:
• H-E-L-L-B-O-T-P-O-L-Y-M-O-R-P-H

File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with a runtime packer.

See a brief description here.

Description inserted by Iulia Diaconescu on Thu, 29 Sep 2005 09:08 (GMT+1)
Description updated by Iulia Diaconescu on Tue, 18 Oct 2005 17:26 (GMT+1)

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