thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Application & OT Security · Foundational

Heartbleed

A 2014 OpenSSL vulnerability (CVE-2014-0160) in the TLS heartbeat extension that let attackers read up to 64 KB of server memory per request.

Definition

A missing bounds check meant the server returned as much memory as the attacker's length field requested, leaking private keys, session cookies and passwords. Remediation required patching, revoking and reissuing certificates and resetting credentials.

Example

After patching, organizations reissued TLS certificates because private keys might have leaked.

Exam tip

A buffer over-read, not an overflow; certificate reissue was part of remediation.

Related terms