The UK's National Crime Agency has warned that the threat from cyber crime is "growing fast" and becoming more "technically proficient and aggressive".
In an interview with the Times, the agency pointed to financial trojans masquerading as legitimate software and distributed denial of service attacks as the biggest cyber crime threats to UK businesses.
TalkTalk became one of the most high-profile UK businesses to fall victims to an online attack when it was hacked last year and the NCA has warned that the threat to firms is increasing as botnets become more "sophisticated".
“These style of attacks can also attempt to mimic human-user behaviour, making them much more difficult to detect,” a spokesperson said.
Botnets have played a significant role in shaping the marketing industry's ad fraud debate after the Chameleon attack was discovered to have affected 120,000 home computers in 2013. The Times claims that attack cost advertisers nearly £4m a month from falsifying activity on pay-per-click ads.