Cisco stopped supporting PIX devices in 2013, but more than 15,000 remain in use. An exploit called BENIGNCERTAIN allowed the NSA to decrypt any traffic from at least 2002 to 2008. The exploit appears to allow an attacker to extract private VPN keys from a vulnerable PIX device simply by sending Internet Key Exchange packets designed to cause the device to dump some of its memory. An NSA malware manual released Aug. 19 by the Intercept suggests the tools were built by the NSA, but the identity of the Shadow Brokers remains a mystery.”]
Source: https://www.cuinfosecurity.com/nsa-pwned-cisco-vpns-for-11-years-a-9354