Gumblar is a computer virus that first appeared in 2009. It has been identified as one of the most malicious viruses in existence. It is characterized by re-directing user’s Google searches and is suspecting to come from flash and PDF files.
Visitors to an infected site will be redirected to an alternative site containing further Malware, which was once gumblar.cn, but has now switched to a variety of domains. The site sends the visitor an infected PDF that is opened by the visitor’s browser or Acrobat Reader. The PDF will then exploit a known vulnerability in Acrobat to gain access to the user’s computer.
The virus will find FTP clients such as FileZilla and Dreamweaver and download the clients’ stored passwords. It also enabled promiscuous mode on the network card, allowing it to sniff local network traffic for FTP details. It is one of the first viruses to incorporate an automated network sniffer.