Spy agency warns of G20 cyber attack risk

Australian businesses have been warned they could fall victim to cyber attacks during next week's G20 summit in Brisbane.

The spy agency, the Australian Signals Directorate, has ramped up its advice to corporate Australia in recent weeks, amid fears the summit of world leaders has made local businesses more of a target.

"Targeting of high profile events such as the G20 by state-sponsored or other foreign adversaries, cyber criminals and issue-motivated groups is a real and persistent threat," the ASD warns in its official G20 cyber security advice.

The agency, whose motto is "reveal their secrets, protect our own" - cites past examples of entities, including Australian government agencies, being targeted due to their involvement in high profile events.

Previous attacks have involved the use of malicious emails dressed up to look like they are from legitimate sources when in face they are designed to compromise computer networks and steal sensitive information.

Cyber attackers could also target public wi-fi networks, the ASD warns.

Australia's chairmanship of the G20 has made computer networks here "a more attractive target for cyber espionage or attack".

CREST Australia, which provides cyber and information security advice, says protest groups could turn to online attacks, because they are cheaper than flying in protesters to physically target next week's G20 event.

Spokesman Greg Rudd says that with so many world leaders in Brisbane, the G20 could prove an irresistible target for hackers.

"They would love to get into the traffic light system, for example, and disrupt that. What they are after really is free international media," he told the ABC on Friday.

The ASD has issued a list of advice to help businesses avoid falling victim, including turfing things such as USB sticks, which are commonly handed out as gifts at events like the G20.

Past experience has shown they can be used to deliver malicious software into business's computer networks and secretly steal sensitive data.

HOW TO AVOID CYBER ATTACKS DURING THE G20:

* Be wary of G20-themed emails that encourage recipients to download files, attachments or visit websites "for more information"

* Signs you have opened a malicious document can include attachments that contain no content, or ones that flicker or flash when opened

* Avoid using web-based email when communicating sensitive information

* Don't use any removable media devices such as USB sticks and CD/DVD disks unless they are yours

* Avoid using public wi-fi networks to stop savvy hackers from stealing your information