On July 6th, information spread that the Italian company known as the Hacking Team were themselves the victims of a cyber attack. In the aftermath of this leak, Vectra researchers have analyzed the leaked data, and identified a previously unknown vulnerability in Internet Explorer 11 that impacts a fully patched IE 11 on both Windows 7 and Windows 8.1.
The hunt for the vulnerability began when we noticed an email from an external researcher who attempted to sell a proof-of-concept exploit to Hacking Team. The email was sent on 02/06/2015 and described an exploitable use-after-free bug in Internet Explorer 11. While Hacking Team ultimately declined to buy the PoC exploit, the email gave enough information for Vectra researchers to find and analyze the vulnerability.
While Hacking Team declined to purchase the PoC exploit, there is a chance the researcher went elsewhere to sell it, meaning that it may have been exploited in the wild.