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W32.Mydoom.M@mm worm

Note: Norton Antivirus 2003 can remove this virus automatically.  You can also download a mydoom removal tool.

 

W32.Mydoom.M@mm is a mass-mailing worm that drops and executes a backdoor, detected as Backdoor.Zincite.A, that listens on TCP port 1034. The worm uses its own SMTP engine to send itself to email addresses it finds on the infected computer. The email contains a spoofed From address, and the Subject and Body text will vary. The attachment name will also vary. Note: Symantec products that support Worm Blocking functionality automatically detect this threat as it attempts to spread. Due to a decreased rate of submissions, Symantec Security Response has downgraded W32.Mydoom.M@mm from a Category 4 to a Category 3 as of July 28, 2004. W32.Mydoom.M@mm is packed with UPX.

 

Also Known As:	W32/Mydoom.o@MM [McAfee], W32/MyDoom-O [Sophos], WORM_MYDOOM.M [Trend], Win32.Mydoom.O [Computer Associates]
Type:	Worm
Infection Length:	28,800 bytes
Systems Affected:	Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP
Systems Not Affected:	DOS, Linux, Macintosh, Novell Netware, OS/2, UNIX

THREAT ASSESSMENT

Wild

• Number of infections: 50 - 999
• Number of sites: More than 10
• Geographical distribution: Low
• Threat containment: Easy
• Removal: Moderate

Damage

• Payload Trigger: n/a
• Payload: n/a
  • Large scale e-mailing: Uses its own SMTP engine to send itself to the email addresses found in the files with certain extensions.
  • Deletes files: n/a
  • Modifies files: n/a
  • Degrades performance: Mass-mailing may clog mail servers or degrade network performance.
  • Causes system instability: n/a
  • Releases confidential info: n/a
  • Compromises security settings: n/a

Distribution

• Subject of email: Varies
• Name of attachment: Varies with .cmd, .bat, .com, .exe, .pif, .scr, or .zip file extension.
• Size of attachment: Varies
• Timestamp of attachment: n/a
• Ports: 1034
• Shared drives: n/a
• Target of infection: n/a

TECHNICAL DETAILS

When W32.Mydoom.M@mm is executed, it performs the following actions:

1. Creates the following registry keys, which mark the computer as infected:
   
   • HKEY_LOCAL_MACHINE\Software\Microsoft\Daemon
   • HKEY_CURRENT_USER\Software\Microsoft\Daemon
     
     
2. Copies itself as %Windir%\java.exe.
   
   Note: %Windir% is a variable. The worm locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.
   
   
3. Drops and executes %Windir%\services.exe, which is detected as Backdoor.Zincite.A. When executed, this file opens TCP port 1034 and listens for remote connections. The backdoor will also probe random IP addresses on port 1034 looking for other infected hosts.
   
   
4. Adds the values:
   
   "Services" = "%Windir%\services.exe"
   "JavaVM" = "%Windir%\java.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the worm and backdoor load when Windows starts.
   
   
5. May create the following files for logging purposes:
   
   • %Temp%\zincite.log
   • %Temp%\<randomly named file>.log
     
     
6. Gathers email addresses from files with the following extensions:
   
   • .adb
   • .asp
   • .dbx
   • .ht*
   • .php
   • .pl
   • .sht
   • .tbb
   • .tx*
   • .wab
     
     
7. Queries the following search engines to harvest additional email addresses for possible distribution:
   
   • search.lycos.com
   • search.yahoo.com
   • www.altavista.com
   • www.google.com
     
     
8. When the worm finds an open Outlook window, it will attempt to send itself to the email addresses that it found.
   
   The email has the following characteristics:
   
   From:
   The From address will be spoofed.
   
   Subject: (One of the following)
   
   • hello
   • error
   • status
   • test
   • report
   • delivery failed
   • Message could not be delivered
   • Mail System Error - Returned Mail
   • Delivery reports about your e-mail
   • Returned mail: see transcript for details
   • Returned mail: Data format error
     
     Body:
     The content contained in the body of the email will vary, based on a number of text options. One of each of the phrases or words in brackets, separated by a "|", will appear:
     
   • Dear user {<recipient's email address>|of <recipient's email domain>},{ {{M|m}ail {system|server} administrator|administration} of <recipient's email domain> would like to {inform you{ that{:|,}|}|let you know {that|the following}{.|:|,}}|||||}
     {We have {detected|found|received reports} that y|Y}our {e{-|}mail |}account {has been|was} used to send a {large|huge} amount of {{unsolicited{ commercial|}|junk} e{-|}mail|spam}{ messages|} during {this|the {last|recent}} week.
     {We suspect that|Probably,|Most likely|Obviously,} your computer {had been|was} {compromised|infected{ by a recent v{iru}s|}} and now {run|contain}s a {trojan{ed|}|hidden} proxy server.
     {Please|We recommend {that you|you to}} follow {our |the |}instruction{s|} {in the {attachment|attached {text |}file} |}in order to keep your computer safe.
     {{Virtually|Sincerely} yours|Best {wishe|regard}s|Have a nice day},
     {<recipient's email domain> {user |technical |}support team.|The <recipient's email domain> {support |}team.}
     
     
   • {The|This|Your} message was{ undeliverable| not delivered} due to the following reason{(s)|}:
     Your message {was not|could not be} delivered because the destination {computer|server} was
     {not |un}reachable within the allowed queue period. The amount of time
     a message is queued before it is returned depends on local configura-
     tion parameters.
     Most likely there is a network problem that prevented delivery, but
     it is also possible that the computer is turned off, or does not
     have a mail system running right now.
     
     
   • Your message {was not|could not be} delivered within <random number> days:
     {{{Mail s|S}erver}|Host} <host used to send the email>} is not responding.
     The following recipients {did|could} not receive this message:
     <<recipient's email address>>
     Please reply to postmaster@{<sender's email domain>|<recipient's email domain>}
     if you feel this message to be in error.
     The original message was received at [current time]{
     | }from {<sender's email domain> ]|{<host used to send the email>]| ]}}
     ----- The following addresses had permanent fatal errors -----
     {<<recipient's email address>>|<recipient's email address>}
     {----- Transcript of {the ||}session follows -----
     ... while talking to {host |{mail |}server ||||}{<recipient's email domain>.|<host used to send the email>]}:
     {>>> MAIL F{rom|ROM}:[From address of mail]
     <<< 50$d {[From address of mail]... |}{Refused|{Access d|D}enied|{User|Domain|Address} {unknown|blacklisted}}|554 <<recipient's email address>>... {Mail quota exceeded|Message is too
     large}
     554 <<recipient's email address>>... Service unavailable|550 5.1.2 <<recipient's email address>>... Host unknown (Name server: host not found)|554 {5.0.0 |}Service unavailable; ] blocked using {relays.osirusoft.com|bl.spamcop.net}{, reason: Blocked|}
     Session aborted{, reason: lost connection|}|>>> RCPT To:<<recipient's email address>>
     <<< 550 {MAILBOX NOT FOUND|5.1.1 <<recipient's email address>>... {User unknown|Invalid recipient|Not known here}}|>>> DATA
     {<<< 400-aturner; %MAIL-E-OPENOUT, error opening !AS as output
     |}{<<< 400-aturner; -RMS-E-CRE, ACP file create failed
     |}{<<< 400-aturner; -SYSTEM-F-EXDISKQUOTA, disk quota exceeded
     |}<<< 400}|}
     The original message was included as attachment
     
     
   • {{The|Your} m|M}essage could not be delivered
     
     Notes:
   • <recipient's email address> is the email address of the person receiving the email.
   • <recipient's email domain> is the domain of the receiver's email. For instance, if the email address is john_doe@example.com, the domain is "example.com."
   • <sender's email domain> is the domain of the sender's email. For instance, if the email address is john_doe@example.com, the domain is "example.com."
   • <host used to send the email> is name of the email server used by the infected computer. The worm gathers this information from the infected computer's registry.
     
     
     Attachment:
     The worm may generate an file name from a domain name of an email address gathered from the computer. For instance, if the worm finds an address john_doe@example.com on the infected computer, the attachment name could contain example.com.
     
     The attachment name may also be one of the following:
     
   • readme
   • instruction
   • transcript
   • mail
   • letter
   • file
   • text
   • attachment
   • document
   • message
     
     with one of the following extensions:
   • .cmd
   • .bat
   • .com
   • .exe
   • .pif
   • .scr
   • .zip
     
     the attachment may have a second extension, which will be one of the following:
   • doc
   • txt
   • htm
   • html
     
     Notes:
   • Approximately 30% of the time, the attachment will be zipped. In these cases the attachment may be compressed several times over.
   • There is a 15% chance the worm will attach a small junk file to the mail instead of a copy of itself.
     
     
     The worm will not send itself to addresses that contain the following strings:
   • mailer-d
   • spam
   • abuse
   • master
   • sample
   • accou
   • privacycertific
   • bugs
   • listserv
   • submit
   • ntivi
   • support
   • admin
   • page
   • the.bat
   • gold-certs
   • feste
   • not
   • help
   • foo
   • soft
   • site
   • rating
   • you
   • your
   • someone
   • anyone
   • nothing
   • nobody
   • noone
   • info
   • winrar
   • winzip
   • rarsoft
   • sf.net
   • sourceforge
   • ripe.
   • arin.
   • google
   • gnu.
   • gmail
   • seclist
   • secur
   • bar.
   • foo.com
   • trend
   • update
   • uslis
   • domain
   • example
   • sophos
   • yahoo
   • spersk
   • panda
   • hotmail
   • msn.
   • msdn.
   • microsoft
   • sarc.
   • syma
   • avp

    

RECOMMENDATIONS

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

REMOVAL INSTRUCTIONS

Removal using the Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of W32.Mydoom.M@mm. This is the preferred method in most cases.

Manual Removal
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as W32.Mydoom.M@mm.
5. Reverse the changes made to the registry.
   

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. Running LiveUpdate, which is the easiest way to obtain virus definitions


3. To restart the computer in Safe mode or VGA mode

Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.
  

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
2. Run a full system scan.
3. If any files are detected as infected with W32.Mydoom.M@mm, click Delete.

1. Click Start > Run.
2. Type regedit
   
   Then click OK.
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   
4. In the right pane, delete the values:
   
   "Services" = "%Windir%\services.exe"
   "JavaVM" = "%Windir%\java.exe"
   
5. Navigate to the keys:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Daemon
   HKEY_CURRENT_USER\Software\Microsoft\Daemon
   
   and delete them.
   
6. Exit the Registry Editor.
   
7. Restart the computer in Normal mode. For instructions, read the section on returning to Normal mode in the document, "How to start the computer in Safe Mode."

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