Worm/Mytob.125440 - Worm

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Summary

Full description

Statistics

Virus:	Worm/Mytob.125440
Date discovered:	02/11/2006
Type:	Worm
In the wild:	No
Reported Infections:	Low
Distribution Potential:	Medium to high
Damage Potential:	Medium
Static file:	Yes
File size:	125.440 Bytes
MD5 checksum:	c80091296c60572af6f300d4ceacd5e4
VDF version:	6.36.00.205 - Thu, 02 Nov 2006 15:58 (GMT+1)
IVDF version:	6.36.00.225 - Thu, 02 Nov 2006 15:58 (GMT+1)

General Methods of propagation:
   • Email
   • Local network

Aliases:
   • TrendMicro: WORM_MYTOB.JP
   • Grisoft: I-Worm/Mytob.AMI
   • VirusBuster: I-Worm.Omega.G
   • Eset: Win32/Mytob.UZ

Platforms / OS:
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

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

Files It copies itself to the following location:
• %SYSDIR%\scvhost32.exe

Registry The following registry keys are added in order to run the processes after reboot:

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
   • "WINTASK"="scvhost32.exe"

– [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices]
   • "WINTASK"="scvhost32.exe"

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "WINTASK"="scvhost32.exe"

The following registry keys are added:

– [HKLM\SOFTWARE\ProductName]
– [HKLM\SOFTWARE\ProductName\ProductID]
– [HKCU\Software\Microsoft\OLE]
   • "WINTASK"="scvhost32.exe"

– [HKCU\SYSTEM\CurrentControlSet\Control\Lsa]
   • "WINTASK"="scvhost32.exe"

– [HKLM\SOFTWARE\Microsoft\Ole]
   • "WINTASK"="scvhost32.exe"

– [HKLM\SYSTEM\CurrentControlSet\Control\Lsa]
   • "WINTASK"="scvhost32.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:
   • Error
   • Good day
   • hello
   • Mail Delivery System
   • Mail Transaction Failed
   • Server Report
   • Status

Furthermore the subject line could contain random letters.

Body:
– In some cases it may contain random characters.
The body of the email is one of the lines:
   • The message contains Unicode characters and has been sent as a binary attachment.
   • The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
   • Mail transaction failed. Partial message is available.
   • Here are your banks documents.
   • The original message was included as an attachment.
   • Mail transaction failed. Partial message %df% available.

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

– Random string
   • body
   • message
   • test
   • data
   • file
   • text
   • doc
   • readme
   • document

    The file extension is one of the following:
   • bat
   • scr
   • exe
   • cmd
   • pif
   • zip

The attachment is a copy of the malware itself.

The email may look like one of the following:

Mailing Search addresses:
It searches the following files for email addresses:
   • wab
   • adb
   • tbb
   • dbx
   • php
   • sht
   • htm
   • txt
   • tmp

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

It combines this with domains from the following list or from addresses found in files on the system

The domain is one of the following:
   • hotmail.com
   • cia.gov
   • fbi.gov
   • juno.com
   • yahoo.com
   • msn.com
   • aol.com

Here you can find examples of generated addresses:
   • ethereal@scram.de
   • gerald@wireshark.org
   • kojak@yahoo.com
   • oabad@noos.fr
   • paolo.abeni@email.it
   • psfales@lucent.com
   • richard@soronlin.org.uk

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

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.
   • ns.
   • relay.
   • mail1.
   • mxs.
   • mx1.
   • smtp.
   • mail.
   • mx.

Network Infection In order to ensure its propagation the malware attemps to connect to other machines as described below.

It drops a copy of itself to the following network share:
• IPC$

Exploit:
It makes use of the following Exploits:
– MS03-049 (Buffer Overrun in the Workstation Service)
– MS05-039 (Vulnerability in Plug and Play)

IP address generation:
It creates random IP addresses while it keeps the first two octets from its own address. Afterwards it tries to establish a connection with the created addresses.

Infection process:
Creates an FTP script on the compromised machine in order to download the malware to the remote location.

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

Server: fuck.randz.**********
Port: 6667
Channel: #omega
Nickname: [OG]%random character string%

– This malware has the ability to collect and send information such as:
    • Malware uptime
    • Information about the network

– Furthermore it has the ability to perform the following action:
    • Execute file

Hosts The host file is modified as explained:

– In this case already existing entries remain unmodified.

– Access to the following domains is effectively blocked:
   • www.symantec.com; securityresponse.symantec.com; symantec.com;
      www.sophos.com; sophos.com; www.mcafee.com; mcafee.com;
      liveupdate.symantecliveupdate.com; www.viruslist.com; viruslist.com;
      viruslist.com; f-secure.com; www.f-secure.com; kaspersky.com;
      www.avp.com; www.kaspersky.com; avp.com; www.networkassociates.com;
      networkassociates.com; www.ca.com; ca.com; mast.mcafee.com;
      my-etrust.com; www.my-etrust.com; download.mcafee.com;
      dispatch.mcafee.com; secure.nai.com; nai.com; www.nai.com;
      update.symantec.com; updates.symantec.com; us.mcafee.com;
      liveupdate.symantec.com; customer.symantec.com; rads.mcafee.com;
      trendmicro.com; www.microsoft.com; www.trendmicro.com

The modified host file will look like this:

Miscellaneous Mutex:
It creates the following Mutex:
• omega

File details Programming language:
The malware program was written in MS Visual C++.

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 Adriana Popa on Mon, 13 Nov 2006 11:45 (GMT+1)
Description updated by Adriana Popa on Mon, 13 Nov 2006 12:34 (GMT+1)

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