After a developer discovered that the social network Path, which is available exclusively through its iOS app, was automatically uploading your address book with all contact data to its servers, there's been a big outcry over the issue of address book privacy. Since then. several other popular social networking apps have also been found to be accessing the address book on iOS without the user's explicit permission, such as Foursquare, Instagram and Twitter, but most – including Path, whose CEO has even publicly apologized – have now received updates that ask the user before transmitting private contact data.
However, this does not prevent other sloppily coded or even malicious apps from doing just that – instead, you'll have to rely on a little jailbreak tweak called ContactPrivacy to block access to your address book from third-party apps.
Provided that your iPhone, iPod touch or iPad is jailbreaked – for example with the recently released Absinthe A5 – you can simply launch Cydia and search for ContactPrivacy there. It's a free download in the BigBoss repository, which is included with Cydia by default. After downloading and installing, you won't find any new app icon or settings entry – whenever an app tries to access your address book, it will simply show a notification through which you can either deny or allow it.
Ryan Petrich, who developed this tool, warns that some apps could crash if access is blocked, though, so apps that automatically attempt to upload your address book in the background might not work properly.
While this is definitely a nice hack that can protect your privacy, for now, the underlying issue lies with Apple – by allowing free access to address book data, while access to location data, in contrast, has always been locked down. Every app that wants to know your location has to ask for permission, and you there's even a dedicated section in the Settings app that allows you to revoke such access at any time. Thankfully, Apple has said that they will be adding a similar option for address book data in a future update. Until then, there's ContactPrivacy!