A mass mailing of a new variant was detected on 19 April 2007.
On the morning of April 19, 2007, Kaspersky Lab, a leading developer of secure content management systems, detected an epidemic caused by Warezov.nf, the latest version of the Warezov email worm. At the peak of the epidemic, the worm accounted for 75 - 80% of all malicious code in mail traffic.
The worm spreads via the Internet as an attachment to infected messages. The attachment does not contain the worm itself, but a component which downloads other malicious programs from the Internet. Infected messages are sent to all email addresses found on the victim machine. The worm is also able to disable and delete antivirus solutions. Warezov.nf is also able to download other malicious programs from a specific site; these programs will provide a malicious user with remote access to an infected machine.
During the height of the outbreak, Warezov.nf caused the overall volume of malicious code to increase to almost 10%. This means that approximately one message in every ten will contain a malicious program. However, by the evening of 19th April, the volume of Warezov.nf in mail traffic began to decline sharply.
An urgent update to Kaspersky antivirus databases containing detection and disinfection routines for Warezov.nf was released on the morning of the 19th, approximately half an hour after the first sample was received. Users of Kaspersky Anti-Virus 6.0/ Kaspersky Internet Security 6.0 should enable proactive protection, and the worm will be blocked without the need to update antivirus databases. All users are recommended to keep their antivirus protection up to date, and not open emails from unknown senders.
About Kaspersky Lab
Kaspersky Lab is the largest antivirus company in Europe. It delivers some of the world’s most immediate protection against IT security threats, including viruses, spyware, crimeware, hackers, phishing, and spam. The Company is ranked among the world’s top four vendors of security solutions for endpoint users. Kaspersky Lab products provide superior detection rates and one of the industry’s fastest outbreak response times for home users, SMBs, large enterprises and the mobile computing environment. Kaspersky® technology is also used worldwide inside the products and services of the industry’s leading IT security solution providers. Learn more at . For the latest on antivirus, anti-spyware, anti-spam and other IT security issues and trends, visit www.viruslist.com.
Related Links
- Virus description of warezov.nf (on viruslist.com)
