A security firm is warning iPhone users not to use the Safari browser to dial telephone numbers because of a bug that could allow attackers to stick victims with a phone bill full of pricey 900-number calls.
The bug likely isnt unique to Apples iPhone, but the most popular device of the moment is the one that SPI Labs chose to check out.
"Its possible a similar type of issue applies to Treos or Windows Mobile devices," the company wrote on its blog post.
Respondents to the post suggested that built-in browsers in other phones, such as BlackBerrys or those from Nokia, are also susceptible given that they provide the same functionality of calling a number from a Web page.
The touch-to-dial function on an iPhone allows the user to dial any phone number displayed on a Web page simply by tapping it. Attackers could use the function to perform a number of malicious actions. As quoted from SPI Labs post, attackers can exploit the bug to:
- Redirect phone calls placed by the user to different phone numbers of the attackers choosing
- Track phone calls placed by the user
- Manipulate the phone to place a call without the user accepting the confirmation dialog
- Place the phone into an infinite loop of attempting calls, through which the only escape is to turn off the phone
- Prevent the phone from dialing
Such attacks could be launched from a malicious site, from a legitimate site with cross-site scripting vulnerabilities, or as part of a worms payload.
Among other things, an attacker could discover a mobile phone users calls to escort services, could trick a target into dialing any phone number without giving consent, or could lock a phone, forcing the victim to either make a call or hard-reset the phone and possibly suffer data loss as a result.
SPI Labs reported the problem to Apple on July 6 and is working with the company to fix the problem. The Labs R&D team hasnt yet investigated how other smart phones handle telephone number/Web browser integration but told eWEEK it plans to do so in the future.
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