Overview[]
On January 25, 2003, the Slammer worm triggered a global Internet slowdown and caused considerable harm through network outages and other unforeseen consequences. According to reports, the Slammer worm (also known as "Sapphire") infected more than 90% of vulnerable computers worldwide within 10 minutes of its release on the Internet, making it the fastest spreading computer worm in history. It doubled in size every 8.5 seconds and achieved its full scanning rate (55 million scans per second) after about 3 minutes. It caused considerable harm through network outages and such unforeseen events as shutting down a 911 emergency call center, causing canceled airline flights and automated teller machine (ATM) failures.
According to media reports, First USA Inc., an Internet service provider, experienced network performance problems after an attack by the Slammer worm, due to a failure to patch three of its systems. The Slammer worm also corrupted for five hours the computer systems at the closed Davis-Besse nuclear power plant located in Ohio. The worm bypassed firewall security, and highlighted possible security issues that may arise whenever plant networks and corporate networks are interconnected. The Davis-Besse corporate network was found to have multiple connections to the Internet that bypassed the plant firewall.[1] As many as five of the 13 Internet root name servers were also slowed or disabled. The Slammer worm reportedly also attacked the Bank of America’s automatic teller machine network and caused severe degradation.[2]
In July 2002, Microsoft had released a patch for its software vulnerability that was exploited by the Slammer worm. Nevertheless, according to media reports, some of Microsoft's own systems were infected by the Slammer worm.
Reported cost estimates of Slammer range between $1.05 and $1.25 billion.