A portion of the U.S. Department of Labor website this week briefly was hosting malicious code that could infect visitors with the Poison Ivy remote access trojan.
According to reports, the compromised page, for the Site Exposure Matrices (SEM), has been cleaned, but it remains offline. SEM normally contains a database "designed to organize, display, and communicate information on the toxic substances found at [nuclear] sites and possible health effects associated with exposure to those substances."
The malicious script on the page directed victims to an attacker-owned site that served an exploit taking advantage of a Microsoft Internet Explorer vulnerability, CVE-2012-4792, which was patched in January, according to security firm Invincea.
"This profile fits the enterprise user machine profile typical of large enterprise and government agencies," wrote Anup Ghosh, Invincea's founder and CEO, in a blog post Wednesday. "The exploit was used to implant a variant of Poison Ivy remote access trojan (RAT) mutated to change the PE [portable executable] magic number to evade network signatures."
He said the attack "bears the hallmarks of a classic watering hole attack," an increasingly common espionage ploy in which adversaries compromise sites that their targets are likely to visit, in this case, individuals working on nuclear weaponry.