FireEye analyzed the hacking group's use of the malware, dubbed the "Dark Edition" of BlackWorm.
The group's Center for Secure Design released a report detailing how to avoid common design flaws.
Several high-profile websites were impacted by a malvertising campaign, which Fox-IT helped dismantle.
The warning comes soon after the Secret Service and DHS issues a warning on the threat.
The study by KPMG and FireEye also found that 49 percent of detected malware was unknown.