Top 5 Most Costly Viruses of All Time

#5. Code Red ($2 Billion)
Code Red, in 2001, is said to be the most expensive virus in history. Self-replicating code exploited vulnerabilities in the Microsoft IIS servers, it spread rapidly as it only needed a network connection to do so; no human interaction or authority was needed. Code Red II was a more malicious version that appeared later on. Code Red II exploited a vulnerability of the indexing service shipped with Microsoft Windows NT 4.0 and Windows 2000 operating systems. Results were website defacement and severe performance degradation. Worse, it would strike multiple times on the same system. It affected organizations like Microsoft and Qwest and even media giant Associated Press. According to research, it caused damage upwards of $2 billion dollars. Microsoft did release a patch to prevent this almost a month before the outbreak. Unfortunately, most operators failed to install it, allowing Code Red and Code Red II to take hold.