Mitigating Denial of Service Attacks
The common view of a denial of service (DoS) attack is that of a flood of requests to a given web server that overwhelms it and renders it useless, at least temporarily. Such attacks have most commonly been perpetrated via botnets, a network of hijacked computers compromised by malware coordinated by a command and control server (specifically, such attacks are referred to as DDoS – distributed DoS). Once a server is hit by such an attack it is too late to do much about it, the network is now flooded; traditional firewalls and intrusion prevention systems can be overwhelmed (or even be the primary target) and the intended damage has been done.
In December 2010, successful DDoS attacks were launched against a number of organisations including PayPal, MasterCard and Visa as part of an operation dubbed “Avenge Assange”, as in Julian Assange, the front man for WikiLeaks, which relied on donations for funding often made via the targeted financial institutions that were now blocking such payments under pressure from the US government. The incidents are good examples of the effective use of DDoS by political pressure groups. PayPal released outstanding funds as a result, but more importantly WikiLeaks received widespread press coverage and was able to present itself as a victim.
