FortiGuard Advisory (FGA-2005-10)

Fortinet advises that its FortiGate security appliances, FortiMail antispam appliances and FortiClient Host Security software protect against the latest MyTob variants, including W32/MyTob.NA-mm, W32/MyTob.MZ-mm and W32/MyTob.MY-mm.

W32/MyTob.NA-mm (aka Doombot.b) is a mass-mailing virus that spreads via SMTP, and resides within a .ZIP file attachment inside emails received from a spoofed sender address. W32/MyTob.NA-mm has the potential to infect innumerable users, based on addresses found on victims' hard drives. After clicking on the infected attachment, the virus has the potential to prevent infected systems from reaching various security Web sites as well as shut down security applications and services on systems that are not running updated antivirus signatures, or not running on-access scanning. W32/MyTob.NA-mm is currently ranked as the number one threat over the last 24 hours, according to Fortinet's FortiGuard Center.

For further information on W32/MyTob.NA@mm, please visit Fortinet's Virus Encyclopedia at:
W32/MyTob.NA@mm

W32/MyTob.MZ-mm (aka Doombot.a) is similar to Doombot.b, differing in that it is currently being distributed in lesser numbers.

For further information on W32/MyTob.MZ@mm, please visit Fortinet's Virus Encyclopedia at:
W32/MyTob.MZ@mm

W32/MyTob.MY-mm is a mass-mailing worm virus that spreads to other systems using its own SMTP engine. Email messages sent by this virus appear to come from a "system administrator" and contain text mentioning problems pertaining to the user's account or password. Once the user clicks on the attachments within the email, the virus terminates certain security and debugging applications, and disables access to security Websites. In addition, the worm opens a backdoor, which allows a remote intruder to access and control the infected computer through an IRC channel.

For further information on W32/MyTob.MY@mm, please visit Fortinet's Virus Encyclopedia at:
W32/MyTob.MY@mm

The latest MyTob mass-mailing viruses are affecting users worldwide and Fortinet rates all three as "Level Three" threats given that they are currently being distributed in very large numbers. To protect against W32/MyTob.NA-mm, W32/MyTob.MZ-mm and W32/MyTob.MY-mm, Fortinet advises against clicking on attachments with executables or zip files from unknown senders. Fortinet also recommends users verify with their systems administrators whether a legitimate email containing a call to action has been sent and to keep antivirus signatures up to date.

For more information on Fortinet's FortiGuard Distribution Network please visit:
http://www.fortiguardcenter.com

Disclaimer:

Although Fortinet has attempted to provide accurate information in these materials, Fortinet assumes no legal responsibility for the accuracy or completeness of the information. More specific information is available on request from Fortinet. Please note that Fortinet's product information does not constitute or contain any guarantee, warranty or legally binding representation, unless expressly identified as such in a duly signed writing.

About Fortinet ( www.fortinet.com ):

Fortinet is the pioneer and leading provider of ASIC-accelerated unified threat management, or UTM, security systems, which are used by enterprises and service providers to increase their security while reducing total operating costs. Fortinet solutions were built from the ground up to integrate multiple levels of security protection--including firewall, antivirus, intrusion prevention, VPN, spyware prevention and anti-spam -- designed to help customers protect against network and content level threats. Leveraging a custom ASIC and unified interface, Fortinet solutions offer advanced security functionality that scales from remote office to chassis-based solutions with integrated management and reporting. Fortinet solutions have won multiple awards around the world and are the only security products that are certified in six programs by ICSA Labs: (Firewall, Antivirus, IPSec, SSL, Network IPS, and Anti-Spyware). Fortinet is privately held and based in Sunnyvale, California.