BEAST

Browser Exploit Against SSL/TLS

"The server is vulnerable to the BEAST attack."

Problem

The Browser Exploit Against SSL/TLS (BEAST) attack affects the SSL 2.0, SSL 3.0 and TLS 1.0 protocols, allowing a bad actor to decrypt the contents of an SSL-encrypted or TLS-encrypted session between a Web browser and a website. The attacker takes advantage of weakness in the block-based cipher suites.

This is a client-side attack where the attacker needs to control the "victims" browser. Most browsers are vulnerable to the BEAST attack.

In a BEAST attack, the attacker acts as a man-in-the-middle and uses specially-crafted plaintext input to decrypt the contents of an SSL-encrypted or TLS-encrypted session between a Web browser and a website. This type of attack allows the attacker to recover sensitive information (e.g., HTTP Authentication cookies).

Solution

  • Enable TLS 1.2 or TLS 1.3 on servers that support these protocols.
  • Enable TLS 1.2 or TLS 1.3 in Web browsers that support these protocols.

Workaround

Disable all block-based cipher suites in your server’s SSL/TLS configuration. Only use this workaround if you can't enable TLS 1.2 or TLS 1.3 on servers and in browsers.

About

DigiCert is the world’s premier provider of high—assurance digital certificates—providing trusted SSL, private and managed PKI deployments, and device certificates for the emerging IoT market. Since our founding almost fifteen years ago, we’ve been driven by the idea of finding a better way. A better way to provide authentication on the internet. A better way to tailor solutions to our customer’s needs. Now, we’ve added Symantec’s experience and talent to our legacy of innovation to find a better way to lead the industry forward, and build greater trust in identity and digital interactions.

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