After hackers played several high-profile pranks with traffic signs, including warning San Francisco drivers of a Godzilla attack, the U.S. government advised operators of electronic highway signs to take "defensive measures" to tighten security.
Last month, signs on San Francisco's Van Ness Ave were photographed flashing "Godzilla Attack! Turn Back" and highway signs across North Carolina were tampered with last week to read "Hack by Sun Hacker."
The Department of Homeland Security's Industrial Control Systems Cyber Emergency Response Team, or ICS-CERT, this week advised cities, highway operators and other customers of digital-sign maker Daktronics Inc to take "defensive measures" to minimize the possibility of similar attacks.
It said that information had been posted on the Internet advising hackers how to access those systems using default passwords coded into the company's software. "ICS-CERT recommends entities review sign messaging, update access credentials and harden communication paths to the signs," the agency said in an alert posted on Thursday.
Jody Huntimer, a representative for Daktronics, declined to say if the recent attacks involved the bug reported by ICS-CERT.
"We are working with the ICS-CERT team to clarify the current alert and will release a statement once we have assessed the situation and developed customer recommendations," Huntimer said via email.
Krebs on Security, a widely read security blog, posted a confidential report from the Center for Internet Strategy, or CIS, which was sent to state security officials. It warned that the pranks created a public safety risk because drivers often slow or stop to view the signs and take pictures.
CIS also predicated that amateur hackers might attempt to hack into other systems in the coming weeks following the May 27 release of "Watch Dogs," a video game from Ubisoft focused on hacking critical infrastructure.
"CIS believes it is likely that a small percent of Watch Dog players will experiment with compromising computers and electronic systems outside of game play," the report said.
© Thomson Reuters 2014