Criminals infected 70 percent of storage devices tied to closed-circuit TVs in Washington DC eight days before the inauguration of President Donald Trump.

The ransomware infection downed 123 of its 187 network video recorders, each controlling up to four CCTVs, and forced the city to wipe its affected IT systems which it says did not include deeper componentry of the Washington DC network.

Public space cameras were out of action between 12 and 15 January. Police eventually noticed four were not recording, The Washington Post reports.

Technicians wiped and rebooted the devices across the city and did not pay ransom demands.

It is unclear if valuable data was lost or if the encrypted data was decrypted for free, or if the ransomware merely crippled the affected network devices.

Victims unable to restore encrypted data with clean back ups need not always pay ransoms; many malware variants have been undone by white hack hackers working under the No More Ransom Alliance, a recent outfit focused on finding and exploiting holes in ransomware that allows free file decryption.

That effort unifies a formerly scattered and siloed, but furious effort by malware researchers to waste the exploding number of ransomware forms hitting end users and enterprises. ®