This indicates an attack attempt to exploit an Information Disclosure vulnerability in Adobe Flash Player.
The vulnerability is due to an error in the Flash API used by Internet Explorer. A remote attacker may be able to leverage the vulnerability to enumerate and read the contents of the files outside the Internet Explorer's Enhanced Protected Mode sandbox.
Adobe Flash Player Desktop Runtime 188.8.131.52 on Windows and Macintosh
Adobe Flash Player for Google Chrome 184.108.40.206 on Windows, Macintosh, Linux and Chrome OS
Adobe Flash Player for Microsoft Edge and Internet Explorer 11 220.127.116.11 on Windows 10 and 8.1
Adobe Flash Player Desktop Runtime 18.104.22.168 on Linux
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor.