The real estate site has warned any of the site's users who try to inquire about rental properties through the site that an authorised third party could have access to their information.
iTWire understands that the phishing attack has had no effect on Nine, which owns 60% of Domain.
Domain chief executive Jason Pellegrino has warned users that personal information such as phone numbers and email addresses may have been obtained by those behind the phishing attack.
"We understand the scammers then contacted some of these people by email to suggest that they pay a ‘deposit’ to secure a rental property on a website nominated by the scammer.
"Importantly, we have had no reports made by an individual directly to Domain who had fallen for the scam.
“There is a risk that some of your personal information may have been accessed by an unauthorised third party that has obtained access to Domain’s systems as a result of a scam targeting one of our systems,” he added.
“It is not yet clear how many users were affected by the scam.”
Commenting on the incident, Ashwin Ram, a cyber security evangelist at Israeli security shop Check Point Software Technologies, said: "Unfortunately, this isn't an isolated episode. Check Point Threat Intelligence data can reveal an Australian organisation is being attacked on average more than 1500 times per month in the last six months.
"These attacks are not always sophisticated and can be prevented using the right security controls, when configured correctly and in line with best practice.
"It is incredibly important for companies to take a prevention approach to cyber security to protect their business, data and customers because once a threat is inside an Australian organisation it can remain undetected for over 290 days on average as recent studies have shown.
"What we also know is that the longer a threat is in an environment, the more damage it can cause, resulting in more cost to an organisation.
"Companies are increasingly required to have a zero tolerance to cyber crimes. In cases where there is a data breach, coming forward and helping customers understand risks and how to avoid further spread is critical. We recommend to all consumers to be extra aware in the coming days."