It should come as no secret to most security-minded individuals with Australia's domestic spy agency, ASIO, issuing warning after warning about possible foreign interference attempts through less secure networks, such as social media and professional networking sites.

The threat extends to all Australians but ASIO has highlighted those holding public office or with security clearances as prime targets.

But while defence personnel were high on the foreign spy wishlist, security and intelligence expert at Australian National University Professor John Blaxand says, they were also challenging targets due to training and awareness of recruitment techniques.

"They are juicy targets, because they have potential to have exponential influence," Professor Blaxland says.

"While it is a rich field if you can tap into it, it's become a more challenging field for those who would want to conduct foreign interference because there's been a heightened awareness [of these concerns among ADF personnel]."

While personnel might be well-trained and defence systems purpose built to avoid any infiltration, social media on the other hand, Professor John Blaxand says, is not.

"The main vulnerability there is with the online presence of individuals and families because the systems that the Defence Force tend to use are pretty secure," Professor Blaxland says.

"[These] systems are hard to crack into from the outside but what's not so hard to crack into is family Facebook posts or LinkedIn ... and Instagram feeds, which actually you can piece together quite a lot of information from."

Professor Blaxland says that information could include the location of assets, the personnel makeup of certain operations, the identity of family members as well as information leading to blackmail attempts.

The threat presents new problems for Defence as it deals with managing threats to personnel outside of the workplace, further blurring the line between work and personal life.

ASIO referenced a case in the United States where an ex-CIA and US Army officer was recruited by a Chinese intelligence officer over LinkedIn, selling high-level defence information for a reported $US25,000.

In Australia, ASIO previously said it had foiled a spy plot to infiltrate the intelligence community. Defence did not confirm whether there had been any attempts in the past five years.

"These are hypothetical [situations] but not far fetched possibilities of how this kind of information can be exploited, and how people's lives can be interfered with," Professor Blaxland says.

In response to the rising threat, Defence says personnel are encouraged to use the publicly available advice offered by the Australian Signals Directorate's Australian Cyber Security Centre.

Those recommendations include the usual suspects - not using the same password for multiple logins, avoiding free WiFi, using screen locks, backing up important files and being suspicious of unsolicited messages.

Outside of those, personnel are free to use whatever social media sites and apps they like on personal devices.

When it comes to Defence devices, however, it's a different ball game altogether.

Defence confirmed general access to social media as well as forums was banned and was managed "closely". Certain devices were also the subject of approvals and defence-related software could only be accessed on Defence devices.

An ABC report earlier this year found TikTok was among one of the apps not authorised on Defence devices, following suit with US military policies.

"The Australian government, including Defence, takes the threat of espionage and foreign interference seriously," a spokesperson said.

"Defence is working as part of a broader whole-of-government effort to counter foreign interference."

But with increasingly unorthodox and creative methods of gathering intelligence and seeking vulnerabilities, the road ahead is going to be challenging for Australia's defence community.

"People do things on the internet [but] they don't realise how exposed they are, how much they trust the internet for anonymity when it's not anonymous," Professor Blaxland says.

While Defence would not comment on the amount, or severity, of attempts that had occurred, Professor Blaxland guessed they were happening "relentlessly" on a daily basis.

What was once a plotline in an outlandish spy thriller was now happening in real life.

"The problem is ... not that long ago this seemed absolutely fanciful... it did seem far-fetched and very Cold War, but the dynamics have shifted significantly in the last few years," Professor Blaxland says.

"The atmospherics are really much more febrile. The circumstances are darker, the scale of these operations is greater, and the implications are more dire.

"So there is a need for a higher level of awareness and of a more self-protective mindset amongst people involved in this space."