A US senator called for answers on Thursday from the maker of a hidden program that tracks activity on smartphones without users knowing or being able to stop it.
Senator Al Franken sent an open letter to California-based Carrier IQ as smartphone titans Apple, Nokia, and Research In Motion (RIM) distanced themselves from the company's controversial software.
"This is potentially a very serious matter," Franken said in the letter.
"It appears that Carrier IQ's software captures a broad swath of extremely sensitive information from users that would appear to have nothing to do with diagnostics -- including who they are calling, the contents of the texts they are receiving, the contents of their searches and the websites they visit."
If Carrier IQ stealthily snoops in ways detailed by smartphone security researcher Trevor Eckhart, it could be breaking federal law, the senator said in his letter.
Franken enclosed a list of questions for Carrier IQ and requested answers by December 14.
He sought details regarding what information Carrier IQ recorded, what was done with it and how it was safeguarded.
Carrier IQ did not respond to requests for comment.
But on its website, it said that "while we look at many aspects of a device's performance, we are counting and summarizing performance, not recording keystrokes or providing tracking tools."
"The metrics and tools we derive are not designed to deliver such information, nor do we have any intention of developing such tools," it continued.
Carrier IQ explained on the website that its software is embedded in smartphones by handset makers and that information collected is for the exclusive use of those customers, who can customize applications to suit their desires.
"Our software is designed to help mobile network providers diagnose critical issues that lead to problems such as dropped calls and battery drain," another notice at the Carrier IQ website maintained.
Apple went on record saying that it stopped supporting Carrier IQ with the new iOS 5 mobile operating system in most of its products and will remove it completely in a future software update.
Apple maintained that gadget users had to opt in to share diagnostic data with Apple, and information was anonymous and encrypted.
Nokia and BlackBerry released media statements denying that they install or authorize Carrier IQ software on handsets.
The releases came after Eckhart described finding hidden Carrier IQ software that tracks activity on Android, BlackBerry and Nokia handsets.
He exposed the workings of Carrier IQ in a video available online.
Eckhart's video showed Carrier IQ software buried deep in an Android-powered smartphone recording buttons pressed, Internet search queries, text messages and locations.
Eckhart typed a text message of "Hello world!" only to have it instantly appear in a Carrier IQ application log in an Android phone.
The software was tricky to find on the device and couldn't be turned off, according to his demonstration.
Carrier IQ had tried to silence Echkart with a cease-and-desist letter threatening legal action, but backed off after lawyers at the Electronic Frontier Foundation (EFF) went to his defense.
"Mr. Eckhart's legitimate and truthful research is sheltered by both the fair use doctrine and the First Amendment," EFF senior staff attorney Marcia Hofmann wrote in a response to the Carrier IQ letter.
Along with Franken, Eckhart wanted details regarding why the Carrier IQ software was vacuuming information about smartphone use and who they shared it with.