The Perils of Free Messaging Apps, Specifically WhatsApp

via Worldcrunch:

WhatsApp is set up to make the service friendly to new users who don’t have to provide their own combination of user name and password – they just use the existing info relating to their phone as login data. Telephone numbers are simply and clearly the basis for user names, and WhatsApp passwords — at least on Android phones — are clearly based on a phone’s IMEI serial number.

Granger discovered that to generate a password out of the IMEI number the app just changes the order of the digits – “your password is likely to be an inverse of your phones IMEI number with an MD5 cryptographic hash thrown on top of it.” What that means is that anybody who knows a phone’s IMEI number can figure out the password.

Many apps use IMEI numbers to identify phones, and any installed program can access that information and pass it on to an external database. In the event that what happened to iPhone this week (a hacker group released one million Apple UDIDs) happens to WhatsApp, and a database generated from the phone serial numbers were to be made public, WhatsApp user accounts would be compromised and become targets for spammers. Not that hackers have lost any time — on gray market sites, databases of Android phone serial numbers and corresponding cell phone numbers are sold under the keyword WhatsApp.

FJP: Filing this under- be smart and secure about your online and mobile life.

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