BEAST (Browser Exploit Against SSL/TLS) was a security vulnerability discovered in September 2011. This vulnerability primarily affected the TLS (Transport Layer Security) protocol, specifically the Cipher Block Chaining (CBC) encryption mode in conjunction with the SSLv3 and TLS 1.0 protocols.
BEAST allowed an attacker to eavesdrop on and decrypt encrypted traffic between a web browser and a server. This was achieved by exploiting a weakness in the way CBC encryption was implemented in SSL/TLS.
To protect against BEAST attacks, it was recommended to upgrade to newer versions of TLS and to use alternative encryption methods that were not vulnerable to this weakness. Many web servers and browsers also implemented patches to mitigate the impact of BEAST.
