W32/Mytob-Z is a mass-mailing worm and Trojan with an IRC backdoor.
W32/Mytob-Z is capable of spreading through various operating system vulnerabilities such as LSASS (MS04-011).
When first run, W32/Mytob-Z copies itself to the Windows system folder as msmgrxp.exe and creates the following registry entries:
HKCU\Software\Microsoft\OLE
WINTASK
msmgrxp.exe
HKCU\System\CurrentControlSet\Control\Lsa
WINTASK
msmgrxp.exe
HKCU\Software\Microsoft\Windows\CurrentVersion\Run
WINTASK
msmgrxp.exe
HKLM\Software\Microsoft\OLE
WINTASK
msmgrxp.exe
HKLM\System\CurrentControlSet\Control\Lsa
WINTASK
msmgrxp.exe
HKLM\Software\Microsoft\Windows\CurrentVersion\Run
WINTASK
msmgrxp.exe
HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices
WINTASK
msmgrxp.exe
W32/Mytob-Z copies itself to the root folder as:
my_photo2005.scr
see_this!!.scr
funny_pic.scr
The worm also drops a helper component to C:\hellmsn.exe which is detected by Sophos as W32/Mytob-D.
W32/Mytob-Z also appends the following to the HOSTS file to deny access to security-related websites:
127.0.0.1 www.symantec.com
127.0.0.1 securityresponse.symantec.com
127.0.0.1 symantec.com
127.0.0.1 www.sophos.com
127.0.0.1 sophos.com
127.0.0.1 www.mcafee.com
127.0.0.1 mcafee.com
127.0.0.1 liveupdate.symantecliveupdate.com
127.0.0.1 www.viruslist.com
127.0.0.1 viruslist.com
127.0.0.1 viruslist.com
127.0.0.1 f-secure.com
127.0.0.1 www.f-secure.com
127.0.0.1 kaspersky.com
127.0.0.1 www.avp.com
127.0.0.1 www.kaspersky.com
127.0.0.1 avp.com
127.0.0.1 www.networkassociates.com
127.0.0.1 networkassociates.com
127.0.0.1 www.ca.com
127.0.0.1 ca.com
127.0.0.1 mast.mcafee.com
127.0.0.1 my-etrust.com
127.0.0.1 www.my-etrust.com
127.0.0.1 download.mcafee.com
127.0.0.1 dispatch.mcafee.com
127.0.0.1 secure.nai.com
127.0.0.1 nai.com
127.0.0.1 www.nai.com
127.0.0.1 update.symantec.com
127.0.0.1 updates.symantec.com
127.0.0.1 us.mcafee.com
127.0.0.1 liveupdate.symantec.com
127.0.0.1 customer.symantec.com
127.0.0.1 rads.mcafee.com
127.0.0.1 trendmicro.com
127.0.0.1 www.microsoft.com
127.0.0.1 www.trendmicro.com
Emails sent by W32/Mytob-Z have the following characteristics:
Subject line:
Error
Status
Server Report
Mail Transaction Failed
Mail Delivery System
hello
Good day
Message text:
Here are your banks documents.
The original message was included as an attachment.
The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
The message contains Unicode characters and has been sent as a binary attachment.
Mail transaction failed. Partial message is available.
The attached file consists of a base name followed by the extentions BAT, CMD, PIF, SCR, EXE or ZIP. The worm may optionally create double extensions where the first extension is DOC, TXT or HTM and the final extension is PIF, SCR, EXE or ZIP.
W32/Mytob-Z harvests email addresses from files on the infected computer and from the Windows address book.