Authentication firm VeriSign has warned that botnets could become more widespread and dangerous as the services become easier to find and cheaper to hire.
VeriSign's iDefence arm said that criminals are advertising botnet services on online forums for just £5.99 (A$10) an hour, which could be used to launch hacking attacks.
The company warned that this cheap and wide availability means that businesses are increasingly at risk of sophisticated attacks from the lowliest of sources.
"Organisations need to be wary of the fact that their critical online applications or services could be taken down in under a day by a criminal renting services from botnet herders at just £5.99 per hour, the same price as a memory stick or DVD," said Rick Howard, director of intelligence at VeriSign iDefense.
VeriSign studied 25 botnet herders across three forums, and found that the average cost of a 24-hour rental is just under £45 (A$79), and includes a range of attack vectors including ICMP, SYN, UDP, HTTP and HTTPS.
The firm said that it had seen many forums using traditional types of marketing to promote their wares, including banner advertising, in a sign of how sophisticated such businesses had become.
VeriSign added that one forum even offered prices for taking down sites that were already prepared to defend against such attacks.
"Businesses and organisations all over the world need to take action now to protect themselves against distributed denial-of-service attacks," said Howard.
"While these attacks are becoming increasingly sophisticated, the criminals targeting your business may not be. Don't leave your company vulnerable to any criminal with an internet connection and a little cash to spare."