Heartbleed, bug within the OpenSSL protocol, is capable enough to expose hundreds of thousands of websites to data theft. The websites affected by the bug include Gmail, Facebook and Yahoo.

Computer systems can easily be tampered via Heartbleed without leaving a trace. This has led to a major outrage among tech enthusiasts as the bug went undetected for about two years.

Companies and government agencies are now rushing to understand which products are vulnerable, then set priorities for fixing them. They are anxious because researchers have observed sophisticated hacking groups conducting scans of the Internet this week in search of vulnerable servers.

Security experts said the vulnerable code is also found in some widely used email server software, the online browser anonymizing tool Tor and OpenVPN, as well as some online games and software that runs Internet-connected devices such as webcams and mobile phones.

Other security experts said that they would avoid using any device with the vulnerable software in it, but that it would take a lot of effort for a hacker to extract useful data from a vulnerable Android phone.