Denial-of-service (DoS) attacks have risen 50% over the last six months, and phishing attacks have rose almost 40% over the same period.
The increases are reported in the biannual Symantec Threat Report.
DoS attacks see hackers overloading a network with data until it collapses, while phishing is where remote attackers send e-mails with fraudulent weblinks to encourage users to hand over passwords to on-line bank accounts.
Symantec said DoS attacks were now running at over 1,400 a day, and that there were now almost eight million phishing attempts per day.
Symantec said those behind internet security attacks were now dominated by people looking to make financial gains rather than get publicity for their malicious skills.
It said the threat of DoS attacks could be used in extortion scams. Symantec said DoS attacks and the rise of phishing were being helped by the increasing use of “bot” or slave computers – infected computers used to spread attacks without their owners’ knowledge.
The government intends to tackle DoS attacks with its proposed justice bill currently before Parliament.
The existing Computer Misuse Act does not directly address DoS attacks and police have had trouble making charges against alleged perpetrators stick.