Antivirus software vendor Malwarebytes successfully cited a rarely used provision in the Communications Decency Act of 1996 (CDA) to win dismissal of a lawsuit that accused the company of using its software to interfere with a rival’s product. Enigma Software Group (ESG), a provider of anti-malware tools, in October 2016 sued rival Malwarebyte for unlawfully characterizing Enigma’s software as potentially harmful to users. The vendor’s software for 10 years previously had not identified either SpyHunter or RegHunter as unwanted software or malware.”]
Source: https://www.darkreading.com/cloud/av-vendors-have-immunity-for-malware-blocking-decisions-court-says

