https://www.compilemymind.com/tags/heartbleed/ Recent content in Heartbleed on Compile My Mind Hugo en Sun, 10 May 2026 00:00:00 +0000 https://www.compilemymind.com/posts/heartbleed-vulnerability-analysis/ Sun, 10 May 2026 00:00:00 +0000 https://www.compilemymind.com/posts/heartbleed-vulnerability-analysis/ <h2 id="1-defining-the-vulnerability">1. Defining the Vulnerability</h2> <h3 id="11-name-and-type">1.1. Name and Type</h3> <p>Heartbleed is a critical flaw classified in cybersecurity literature as a <strong>Buffer Over-Read</strong> vulnerability. It stems from how OpenSSL handles the TLS Heartbeat extension (RFC 6520). The core issue is remarkably simple: the server never verifies the payload length declared by the client against the actual size of the transmitted data.</p> <p>In the C source code, this <code>uint16_t</code> length parameter is passed directly to the <code>memcpy</code> function as an input. Consequently, if an attacker sends just 1 byte of data but claims, &ldquo;I sent 65,535 bytes,&rdquo; the server unquestioningly reads a 64 KB chunk from its own memory and transmits it back to the client.</p>