The partial shutdown of the federal government is having an impact in ways both anticipated and not. One that probably falls under the latter is expiring TLS certificates that leave some .gov websites marked as "unsafe" or completely inaccessible from most browsers.

Websites from NASA, the Department of Justice, and the Court of Appeals are among those using one of the 80 certificates that have not been renewed since the beginning of the shutdown.

"The government shutdown has left a mark on the digital world. Several government websites now greet users with a 'CERT_DATE_INVALID' warning in place of the website itself. At best, this isn't a good look for the departments concerned. At worst, the thousands of Americans who rely on these websites are left cut off from the services they need," says Martin Thorpe, enterprise architect for Venafi.

Some experts say the issue goes beyond mere Web page inaccessibility. "I think the biggest risk is far beyond expired SSL certificates. How many critical governmental systems are currently unmaintained, outdated, and thus vulnerable?" asks High-Tech Bridge CEO Ilia Kolochenko. "It seems to be a great opportunity for nation-state hacking groups to exploit US momentary weakness to steal or alter extremely sensitive information."  

Franklyn Jones, CMO at Cequence Security, agrees with Kolochenko and points to specific risks in the moment. "It creates a great opportunity for bad actors to launch automated bot attacks, testing previously stolen credentials to gain access to private accounts on government sites," he explains.

Read more here and here.