Hackers are playing off the buzz about Apple's iPhone to craft malware targeting people who plan to buy the device or believe they've won one in a contest.

Over the weekend, Sunbelt Software spotted a custom-built Trojan horse that redirects unwitting iPhone shoppers to a bogus website when they surf to iphone.com, a legitimate address that normally takes users to Apple's own iPhone site.

The Trojan, which has not yet been named by antivirus vendors, produces a pop-up when users on infected Windows PCs head to either yahoo.com or google.com. The pop-ups tout iPhone.com as ‘the only place to buy iPhone’, and use the Apple logo and the actual price ($499) of the 4GB model to add weight to the offer.

"On this infected system, you get directed to a custom 'iphone.com' which actually is a fake site," said Alex Eckelberry, Sunbelt's CEO, in a blog entry.

The Trojan pulls content from the infected machine, and injects code into Microsoft's Internet Explorer browser to build what looks like an Apple-owned site. As the duped buyer makes his way through the purchase screens, he selects the iPhone model, its colour - a dead give-away, since the iPhone comes in only one design - and then is told to send the money via Western Union or MoneyGram. According to Eckelberry, the recipient is in Latvia, a hacker hotbed like its Baltic neighbours and former occupier, Russia.

Other iPhone-associated scams are on the prowl, added Secure Computing, another security software maker. Secure has detected a rogue website, for example, that hosts a multi-exploit strike package, and found spam that dangle free iPhones in front of users to get them to click through a link to the attack URL.

The malicious site, said Secure, packs more than 10 exploits against both patched and unpatched ActiveX vulnerabilities in Windows and/or Internet Explorer. If any one of the exploits is successful, the PC is hijacked and turned into a spam-spewing bot. Rootkit components in the malware try to cloak it from anti-virus scanners.

"This threat is particularly insidious in that scripts contain exploit code for multiple vulnerabilities to improve the hacker's chances of gaining the necessary access to install the rootkit/spam bot malware," said Paul Henry, vice president of technology evangelism at Secure.

Scambusters.org, a site that has been tracking Internet scams and hoaxes since 1994, which posted a list of iPhone scam predictions last week, has already seen several prove out, including its No. 6, ‘Fake iPhone websites and phishing scams’ and No. 7, ‘iPhone viruses, Trojans, and spyware’.

See also

First look: Hands-on with the iPhone

Hackers could unlock iPhone today

The iPhone killers: best products of 2007

iTunes update adds iPhone support

iPhone software aids Amazon shoppers

Tackling the iPhone mob