Imperva , a leading provider of Internet firewall services that help Web sites block malicious cyberattacks, alerted customers on Tuesday that a recent data breach exposed email addresses, scrambled passwords, API keys and SSL certificates for a subset of its firewall users. Redwood Shores, Calif.-based Imperva sells technology and services designed to detect and block various types of malicious Web traffic, from denial-of-service attacks to digital probes aimed at undermining the security of Web-based software applications. Image: Imperva Earlier today, Imperva told customers that it learned on Aug. 20 about a security incident that exposed sensitive information for some users of Incapsula , the company’s cloud-based Web Application Firewall (WAF) product. “On August 20, 2019, we learned from a third party of a data exposure that impacts a subset of customers of our Cloud WAF product who had accounts through September 15, 2017,” wrote Heli Erickson , director of ana...