CVE Catalog

CVE-2011-3389

Medium
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Very high risk
73.33%

99th percentile - higher than 99% of all known CVEs

Summary

A vulnerability in the SSL protocol where, in certain configurations (including Microsoft Windows, Internet Explorer, Firefox, Chrome, Opera), data is encrypted using CBC mode with chained initialization vectors, allowing man-in-the-middle attackers to obtain plaintext HTTP headers. The BEAST attack uses a blockwise chosen-boundary attack (BCBA) on an HTTPS session combined with JavaScript code using WebSocket, Java URLConnection, or Silverlight WebClient APIs.

Risk Assessment

A man-in-the-middle attacker can intercept sensitive HTTP headers (e.g., session cookies) from encrypted HTTPS sessions, potentially leading to session hijacking and unauthorized data access. The risk affects organizations using vulnerable browsers and SSL configurations.

Recommendation

Enable BEAST mitigations such as 1/n-1 record splitting on the server or client side, and prioritize AES-GCM ciphers over CBC. Update browsers and SSL libraries to the latest versions.

Related vulnerabilities

Original NVD description (English source)

The SSL protocol, as used in certain configurations in Microsoft Windows and Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, Opera, and other products, encrypts data by using CBC mode with chained initialization vectors, which allows man-in-the-middle attackers to obtain plaintext HTTP headers via a blockwise chosen-boundary attack (BCBA) on an HTTPS session, in conjunction with JavaScript code that uses (1) the HTML5 WebSocket API, (2) the Java URLConnection API, or (3) the Silverlight WebClient API, aka a "BEAST" attack.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS