IBM report: Most successful exploits from the past year weren’t zero-days. Publicly disclosed vulnerabilities decreased by 5.4 percent in 2007 over 2006, but the number of high-severity bugs increased by 28 percent. Botnet operators typically use known bugs for efficiency — and economic — reasons. There are plenty of zero-day attacks dangerously alive and well out there, security experts say. There’s no sure-fire way to measure number of successful attacks, says David Aitel, CEO for Immunity Inc.”]
Source: https://www.darkreading.com/analytics/report-zero-days-are-now-attackers-second-choice

