Mobile apps could be abused to make expensive phone calls

Mobile applications often don't warn users before a call is made, which a developer says could be abused

A security precaution skipped in mobile applications such as Facebook's Messenger could be abused to make an expensive phone call at a victim's expense, a developer contends.

Phone numbers often appear as links on a mobile device. That is possible by using a Uniform Resource Identifier (URI) scheme called "tel" to trigger a call.

URI schemes are a large family of descriptions that can tell a computer where to go for a certain resource, such as launching a mail application when an email address is clicked.

Andrei Neculaesei, a full-stack developer with the wireless streaming company Airtame in Copenhagen, contends there's a risk in how most native mobile applications handle phone numbers.

If a person clicks on a phone number within Apple's mobile Safari browser, a pop-up asks if a person wants to proceed with a call.

But many native mobile applications, including Facebook's Messenger and Google's +, will go ahead and make the call without asking, Neculaesei wrote on his blog.

Mobile apps can be configured to display a warning, but on most applications it's turned off, Neculaesei said via email on Thursday.

He found a malicious way to abuse the behavior. He created a Web page containing JavaScript that caused a mobile application to trigger a call after someone merely viewed the page. The JavaScript automatically launches the phone number's URI when the page is opened.

A demonstration on his blog showed how a malicious link, sent through Facebook's Messenger, will launch a call when viewed. Neculaesei wrote that someone could create a link that when viewed immediately launches a call to a premium-rate number, which the attacker gets the revenue from.

His testing found that Facebook's Messenger app, Apple's Facetime, Google's Gmail and Google + applications do not warn users before launching a call.

Facebook and Google couldn't be immediately reached for comment. Neculaesei wrote that he only tested a few big-name apps, but it's probable that smaller teams and platforms haven't thought about the risk either.

Neculaesei's finding dovetails with research presented earlier this month at the Bsides security conference in Las Vegas.

Guillaume K. Ross, an information security consultant in Montreal, found that URI schemes can be abused, resulting in data losses or compromising a person's privacy. A video of his presentation is online.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Join the CSO newsletter!

Error: Please check your email address.

Tags AppleGooglesecurityExploits / vulnerabilitiesFacebook

More about AppleFacebookGoogleMessenger

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Jeremy Kirk

Latest Videos

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

  • 150x50

    IDG Live Webinar:The right collaboration strategy will help your business take flight

    Speakers - Mike Harris, Engineering Services Manager, Jetstar - Christopher Johnson, IT Director APAC, 20th Century Fox - Brent Maxwell, Director of Information Systems, THE ICONIC - IDG MC/Moderator Anthony Caruana

    Play Video

More videos

Blog Posts

Market Place