A default setting in Apple's iPhone that automatically responds to read-receipt requests on emails sent to the device could be exploited by spammers, according to analyst firm Ovum.
An Apple Australia spokesman could not be reached for comment.
Principal analyst at Ovum UK Graham Titterington told CRN the default setting was "certainly a problem".
He believed the automatic acknowledgement that emails had been 'read' by the iPhone user could result in that user's email address being added to global spam lists.
"If you acknowledge a spam email, then they have verified that your email account is active, and it is then likely to be more actively targeted by other spammers," he said.
"It will seriously impair [users'] productivity as their inbox gets clogged with spam, much of which could be harmful or unpleasant."
Chris Herrmann, managing director of Sydney integrator Far Edge Technology suspected the default setting had resulted in more spam coming to his inbox.
He also expressed concern to CRN that the setting loophole could be exploited in a way that presented "a very serious threat to iPhone users' data".
"[The data] could be accessed and transmitted unwittingly and this could incur huge excess usage charges from the user's telecommunications provider," he said.
Campaigning for default change
Titterington believed the only way the issue could be addressed effectively was for Apple to alter the default configuration of the iPhone.
He suggested that the iPhone's default setting should be to deny receipt requests automatically rather than accept them.
He conceded Apple "probably doesn't want to complicate the user experience by requiring the user to accept or deny read-receipt requests" that come with email messages sent to the device. Making the denial a default setting was a better option, he said.
"Users might not know how to respond to such a question anyway," he said.