The timing vulnerability resides in the Transport Layer Security (TLS) protocol and hackers could exploit it to access sensitive data in transit. The Raccoon attack is a server-side attack that exploits a side-channel in the cryptographic protocol (versions 1.2 and lower) which allows the attackers to extract the shared secret key used to secure communications. The flaw is really hard to exploit and relies on precise timing measurements and on a specific server configuration to be exploitable. F5, Microsoft, Mozilla, and OpenSSL have already released security patches to address the vulnerability.”]
Source: https://securityaffairs.co/wordpress/108144/hacking/raccoon-tls-attack.html