This fact rarely comes out on Law & Order, but for some crime pays. And pretty well. Developers of ransomware well paid and malware cheap to buy.
Mozilla issued a security update stating that the newly released Thunderbird 52.4 , Firefox 56 and Firefox ESR 52.4 patch 10 vulnerabilities, two rated critical, five high and three moderate found in earlier iterations of the software.
Microsoft's October Patch Tuesday release covered a wide spectrum of problems with the majority possibly resulting in remote code execution (RCE) and CVE-2017-11826 being publicly disclosed and actively exploited.
Apple issued a supplemental security update for macOS High Sierra 10.13 to patch two issues, one of which fixes a keychain password issue discovered last week.