Gumblar is a malicious JavaScript trojan horse file that redirects a user's Google searches, and then installs rogue security software.
The PDF will then exploit a known vulnerability in Acrobat to gain access to the user's computer.
Newer variations of Gumblar redirect users to sites running fake anti-virus software.
[3] However, many badware variants have emerged after that and they connect to other malicious servers via iframe code.
Gumblar resurfaced in January 2010, stealing FTP usernames and passwords and infecting HTML, PHP and JavaScript files on webservers to help spread itself.