More than 32,000 individuals and 4000 US organisations have potentially been compromised as part of a new malware campaign that targets local institutions like community halls, shopping centres and schools.
The compromised hosts belonged to government, technology and defence industry staff who RSA said were targeted in a single attack by criminals wanting to get inside the companies' networks.
The attackers hoped hijacked machines would be taken back inside the corporate network where the malware would infect more machines and steal data.
Attackers had infected the websites of banks and even schools near the residential areas where employees likely lived.
These sites served as community hubs and were likely to be visited by many of the targeted individuals, RSA chief information security officer Eddie Schwartz told SC.
The security firm dubbed the sites "watering holes" in recognition of their ability to draw crowds, and as a hunting ground for predators.
Initial reports from RSA's server logs reported most victims were located in Massachuttes and Washington DC.
However, Schwartz said the attacks were happening elsewhere including Asia.
"These [victims] are your school web sites and banks -— any organisation within certain geographic locations," Schwartz said.
"I bet any money it's happening in Australia."
Those exploit sites would check that a victim was running both Windows and a vulnerable version of Internet Explorer before an instance of the Gh0st remote access tool was installed.
That tool granted attackers a host of functions including the ability to install malware and grab data.
RSA researchers are drafting a paper expected to be released in coming weeks that details more information on the attacks.