The email was flagged urgent and screamed in capital letters: YOUR IMMEDIATE ATTENTION REQUIRED! The message said a software update was needed to avoid major system disruption, and to click a link and enter a network password. The NRC employee who received the email thought the message looked suspicious. Instead of clicking on the link, she forwarded the message as an attachment to the NRC’s Computer Security Incident Response Team.
Within minutes, a CSIRT member was analyzing the email on a computer unconnected to the NRC network. He quickly determined the message was bogus, a “phishing” attempt to gain unauthorized access to the system. He instructed the employee to delete the message and block the sender to avoid receiving any further attempted intrusions from that Internet address.
Had the employee provided her username and password, she could have exposed the NRC’s computer network and its sensitive information to compromise and possible disruption. Personal information about NRC employees would have been at risk, as well as sensitive pre-decisional information about agency policies and licensees. While Safeguards and classified information about the security and status of nuclear plants is maintained on separate higher security systems, the information we process on the NRC corporate network must also be protected.
CSIRT, part of the NRC’s Computer Security Office, is a small group of experts, all highly trained in cyber defense. Their mission is to detect and thwart attacks on the NRC’s computer networks and prevent “spills” of sensitive information. Such attacks can come through phishing attempts, such as the fictional incident described above, malware implanted in website advertisements or viruses and malware on portable data devices.
The team routinely works with other federal agencies, including the Homeland Security Department’s U.S. Computer Emergency Response Team (US-CERT) to stay up to date on the latest vulnerabilities. They even practice “white hat” hacking to test the NRC’s systems.
As a response team, CSIRT investigates suspicious emails that have already passed through the NRC’s extensive SPAM filters and Internet firewall, robust cyber security defenses mounted by the Office of Information Systems.
About 10 million emails are directed to NRC.gov addresses each month, and nearly 90 percent of them are blocked by the agency’s network security technologies as spam or for carrying viruses or suspicious attachments, says Mike Lidell, IT Specialist in the OIS Security Operations and Systems Engineering Branch. The OIS team administers the NRC’s firewalls, intrusion detection systems and spam filters.
While the percentage of blocked emails seems high, Lidell says it’s pretty much “par for the course” for any large organization or government agency. Emails that get through the initial line of defense are scanned again by the internal servers and a third time by the end-user’s individual computer. Internet data returned from the Web is scanned by NRC servers and individual workstations as well to guard against “drive-by downloads” of malicious software.
As Lidell points out, the “defense in depth” is necessary because the attacks are always evolving and changing. Thorne Graham, CSIRT’s team leader, praises a fourth line of defense against email attacks on the agency’s network: The NRC’s 4,000 employees. All NRC employees take annual online computer security training.
“Our best defense is the individual employee,” Graham says. “Security is everyone’s business.”