New vulnerability named The Heartbleed Bug was discovered in OpenSSL 1.0.1. through 1.0.1f(inclusive). Unfortunatelly these version were rapidly deployed in last two years by modern operating systems. Vulenrability allows reading the memory of the systems protected by the vulnerable version of OpenSSL without leaving a trace. Among leaked informations might be private keys, user names, passwords, e-mails etc. One can fix it by upgrading the system or applying the patch.