Once the hackers got into the PHP-based websites, they inserted toolkits to turn them into launch pads for their distributed denial-of-service attacks. Hackers then launched the attacks on banks by connecting directly to the compromised PHP-based websites and sending them commands, or took advantage of intermediate servers, proxies or scripts to make the websites do their bidding. InformationWeek lists three attack tools used by the hackers: KamiKaze, AMOS, and the "itsokaynoproblembro" toolkit, also known as Brobot.

Several major banks have been targeted including Bank of America, JP Morgan/Chase, HSBC and Well Fargo. The main problem was out-of-date software running on the site containing known security issues the attackers could exploit to install their own software.

If a hacker can break into a PHP-based website to use it as a staging area for an attack on a different website, they can also use that website to store stolen information. InformationWeek cited the example of the Eurograbber attack campaign, revealed earlier this month. The gang involved in that campaign stole $47 million from more than 30,000 corporate and private banking customers - and used PHP-based websites into which they hacked to store stolen information.