Adblock in Safari may die with IOS 9 ad-killer feature

Apple announced a series of improvement for it IOS 9, including a content blocker can kill a lot of applications similar the popular AdBlock.

A lot have been talks about IOS 9, and now looks like Apple included an ad-blocking feature in its OS, I would say it is a great news for its customers, but for the developers of applications like Adblock it could become a nightmare.

“The new Safari release brings Content Blocking Safari Extensions to iOS. Content Blocking gives your extensions a fast and efficient way to block cookies, images, resources, pop-ups, and other content.” States Apple.

The content blocking doesn’t came natively, users will need to install a blocking software that interacts with Safari (via JSON),

“Your app extension is responsible for supplying a JSON file to Safari. The JSON consists of an array of rules (triggers and actions) for blocking specified content. Safari converts the JSON to bytecode, which it applies efficiently to all resource loads without leaking information about the user’s browsing back to the app extension. Xcode includes a Content Blocker App Extension template that contains code to send your JSON file to Safari. Just edit the JSON file in the template to provide your own triggers and actions. The sample JSON file below contains triggers and actions that block images on webkit.org”

But why such feature can kill applications like AdBlock?

“In short, either this new API will improve Adblock Plus performance on Safari or it will force us to rely upon an inferior blocking format that would essentially kill adblocking on Safari.” States Sebastian Noack from AdBlock.

“So far very little is known about Content Blocking Extensions, available in Safari 9 and iOS 9. However, according to the announcements there are so called “block lists”, which are JSON files, that can be registered by the extension.”

“This mechanism is entirely different from the one used by Adblock Plus on any other platform (including current versions of Safari), where we can run arbitrary code on request, blocking requests depending on their URL and context.”

“With this new mechanism, we’d need to convert Adblock Plus filter lists to a block list like the one above. However, most of our filters aren’t as simple as the example above. So, we are nervously awaiting how powerful their block lists will be, most importantly when it comes to matching the document domain and request type, as well as regular expression matching of URLs and recursive exception rules.”

In this phase developers can only wait for Apple information on iOS 9 and its content-blocker working mode, either will help them to improve their adblocking software.

About the Author Elsio Pinto

Elsio Pinto (@high54security) is at the moment the Lead Mcafee Security Engineer at Swiss Re, but he also as knowledge in the areas of malware research, forensics, ethical hacking. He had previous experiences in major institutions being the European Parliament one of them. He is a security enthusiast and tries his best to pass his knowledge. He also owns his own blog http://high54security.blogspot.com/

Edited by Pierluigi Paganini

(Security Affairs – AdBlock, iOS 9)

Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.