Black Arrow Cyber Threat Briefing 08 January 2021: Ryuk gang estimated to have made more than $150 million from ransomware; China's hackers move to ransomware; Amid hardened security, attackers seek softer targets; Hackney Council files leaked online after cyber attack; PayPal users targeted in new SMS phishing campaign; the rise of cyber-mercenaries; Declutter Your Devices to Reduce Security Risks