An Interior Department watchdog recommended the U.S. Geological Survey ratchet up internet security protocols after discovering its networks had been infected with malware from pornography sites.

The agency’s inspector general traced the malicious software to a single unnamed USGS employee, who reportedly used a government-issued computer to visit some 9,000 adult video sites, according to a report published Oct. 17.

Many of the prohibited pages were linked to Russian websites containing malware, which was ultimately downloaded to the employee’s computer and used to infiltrate USGS networks, auditors found. The investigation found the employee saved much of the pornographic material on an unauthorized USB drive and personal Android cellphone, both of which were connected to their computer against agency protocols.