Hi. I’m Prateek Gianchandani.

Security Researcher. Mountaineer. Diver.

iOS Application Security Part 17 – Black-Box Assessment of iOS Applications using INTROSPY

In this article, we will look at how we can use Introspy for Black-box assessment of iOS applications. Introspy is developed by ISEC partners and its github page can be found here. Introspy consists of two seperate modules, a tracer and an analyzer. It is undoubtedly one of the most powerful tools for analyzing the security of iOS applications.

The first step is to install the Introspy tracer on your device. You can download the debian package from here. Once it is downloaded, just upload it and install on your device. The image below shows how to perform all the above mentioned steps.

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IOS Dev - Storing Info in Keychain with NSUserDefaults like syntax

Recently, i decided to improve the security of one of my applications by storing some of the information that i was previously saving in NSUserDefaults in the Keychain. Basically, this doesn’t make that much of a difference if your device is jailbroken. However, if your device is not jailbroken then it is possible to fetch the information saved by NSUserDefaults but not from the Keychain. This is because NSUserDefaults saves the information in an unencrypted format in a plist file inside the application sandbox which can be easily fetched. It can also be fetched from an iTunes backup. Hence, saving info in the Keychain adds an extra layer of security in that case.

I started looking for some Keychain Wrappers and bumped into this amazing library from Github named PDKeychainBindingsController. I found it ridiculously simple to use.

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iOS Application Security Part 16 – Runtime Analysis of iOS Applications using iNalyzer

In the previous article, we looked at how we can perform static analysis of iOS Applications using iNalyzer. In this article, we will look at how we can use iNalyzer to perform runtime analysis of iOS applications. We can invoke methods during runtime, find the value of a particular instance variable at a particular time in the app, and basically do anything that we can do with Cycript.

In the last article, we were successfully able to generate the html files via Doxygen and open it up to view class information and other information about the app. For runtime analysis, we will be using the Firefox browser. The developer of this tool has personally recommended me to use Firefox as this may not work on other browsers. However, it seemed to be working fine for me on Chrome as well.

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iOS Application Security Part 15 – Static Analysis of iOS Applications using iNalyzer

In the previous article, we looked at how we can use Sogeti Data protection tools to boot an iDevice using a custom ramdisk with the help of a bootrom exploit. In this article, we will look at a tool named iNalyzer than we can use for black box assessment of iOS applications. iNalyzer allows us to view the class information, perform runtime analysis and many other things. Basically it automates the efforts of decrypting the application, dumping class information and presents it in a much more presentable way. We can also hook into a running process just like Cycript and invoke methods during runtime. iNalyzer is developed and maintained by AppSec Labs and its offical page can be found here. iNalyzer is also made available open source and its github page can be found here.

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iOS Application Security Part 14 – Gathering information using Sogeti Data Protection tools

In the previous article, we looked at how we can boot a device using a custom ramdisk using Sogeti Data protection tools. In this article, we will look at how we can use some of their tools to gather information from the device like fetching the keychain information, dumping the entire filesystem or even bruteforcing the passcode.

Until the previous article, we had successfully set up a connection to the device using usbmux, ssh’ed into the device and had mounted the partitions. Here is what these partitions contain.


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iOS Application Security Part 13 – Booting a custom Ramdisk using Sogeti Data Protection tools

In the previous article, we looked at how we can use Keychain-Dumper and Snoop-it to analyze and dump the contents of the Keychain from an iOS device. In this article, we will look at how we can boot a non-jailbroken device using a custom ramdisk and analyze the contents of the device.

So what is the need of booting a device using a custom ramdisk ? Imagine a scenario where you only have temporary access to a device and you can’t jailbreak it. You just have access to the device for say like 30 minutes. In that time, you can boot the device using a custom ramdisk, brute force the passcode, and dump all the information for later analysis. The best thing is that the device does not need to be jailbroken in order for you to carry out this attack. Ofcouse, if the device is using a alphanumeric passcode, then it might take even more time to bruteforce the passcode. You can imagine this as similar to booting a windows machine with a Linux live CD, and then mounting the windows partition and then using the Linux OS to access the contents of the hard drive. Read on →

Mind over Body !
Stok Kangri Summit Day
16,300 ft -> 20,187 ft -> 16,300 ft

9:40 pm - Stok Kangri Base Camp - 16,300 ft

Why climb Everest ? Because it’s there.

George Mallory

I crawled out of my tent after a 3 hour restless sleep. We were supposed to leave at 10:30 pm for the summit. It was a perfectly clear day, something that we had really wished for. There was a storm at the same time the night before. I looked up and saw all the stars. It was an unbelievably beautiful sight. I could easily make out some of the constellations and the milky way galaxy. In those 15 mins, i saw atleast 4-5 shooting stars.

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What to expect from the new iPhone (5S/5C) - Rumor roundup

The smartphone world is buzzing about rumors for the new Iphone. The new Iphone is rumored to be launched on September 10 in an event in San Francisco, which means that the invitations for the event would be sent to the press sometime around September 3. This time, Apple is reported to be releasing two models of iPhone, one is the iPhone 5s and the other a cheaper variant, reportedly named as the iPhone 5C. Here is a complete rumor roundup from multiple sources about the next generation iPhone.

Fingerprint Sensor

There is absolutely no doubt regarding the fact that the new iPhone will come with a biometric fingerprint sensor.Code for biometric scanning has already been discovered in the beta versions of IOS 7 (by Hamza Sood) released to developers.

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iOS Application Security Part 12 – Dumping Keychain Data

In the previous article, we looked at the different ways in which we could analyze the network traffic and the api calls being made through an iOS application. In this article, we will look at how we can dump the contents of the Keychain from an iOS device.

Keychain Basics

According to Apple, a Keychain in an iOS device is a secure storage container that can be used to store sensitive infromation like usernames, passwords,network passwords, authentication tokens for different applications. Apple itself uses the Keychain to store Wi-fi network passwords, VPN credentials etc. It’s a sqlite database file located at /private/var/Keychains/keychain-2.db and all the data stored in it is encrypted. Developers usually want to leverage this feature of the operating system to store credentials rather than storing it themseleves in NSUserDefaults, plist files etc. The reason for this could be that the developer may not want the user to log in everytime and hence store the authentication information somewhere in the device and use it to log in the user automatically whenver the user opens up the app again. The keychain information for every app is stored outside of its sandbox.

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iOS Application Security Part 11 – Analyzing Network Traffic over HTTP/HTTPS

In the previous article, we looked at iOS filesystem and forensics. In this article, we will be looking at how we can analyze the network traffic flowing across an iOS device. Analyzing the network traffic for an application could be helpful in many ways. It could help us deduce how the application is managing the session of its users, the endpoints to which the application makes the call, how the application works internally etc. We will also look at how we can analyze network traffic over SSL.

There are both active and passive ways of sniffing traffic on a network. In case you are interested in analyzing the traffic for a particular device over a network remotely, wireshark is the tool to go for. Just open up Wireshark, start sniffing over the network and add a filter (for e.g ip.addr == so that it shows only the traffic sent or received from your iOS device. It is possible that you may lose some packets if you don’t have a good wireless card.

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iOS Application Security Part 10 – iOS Filesystem and Forensics

In this article, we will be looking at the iOS filesystem, understand how the directories are organized, look at some important files, and look at how we can extract data from database and plist files. We will look at how applications store their data in their specific directories (sandbox) and how we can extract them.

One of the important things to note is that in all the previous articles, we have been logging in to the device as the user root. There is another kind of user with the username mobile. A mobile user has less privileges than a root user. All the applications run with the user mobile, with the exception of Cydia and some other applications which run with root privileges. Some of Apple’s internal daemons or services also run with root privileges. A quick ps aux will make this very clear. On the extreme left, you will see the USER column. We can see that Cydia runs with root privileges, whereas all other applications run with mobile user, for e.g /Applications/AppStore.app/AppStore while some of the daemons for e.g /usr/sbin/wifid run with root privileges. Some other applications that you install via Cydia may also run with root privileges. By default, once you jailbreak the device, the password for both root and mobile user is alpine.

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iOS Application Security Part 9 – Analyzing Security of iOS Applications using Snoop-it

In some of the previous articles, we have looked at how we can dump class information of iOS apps using class-dump-z, hook into the runtime using Cycript and perform runtime manipulation and method swizzling, analyze the flow of the app using gdb etc. However, there could be a much better way of doing these things. We shouldn’t be using seperate tools for all these tasks. It would be great if a tool could perform all these tasks and at the same time display the information in a much more presentable way.

Snoop-it is a tool that solves these problems. It allows for runtime analysis and blackbox security assessment of iOS apps by retrofitting existing apps with debugging and runtime tracing capabilities. It also provides a very neat web interface. At the time of writing of this article, Snoop-it is not released yet but is a couple of weeks away from launch. I mailed the authors and they were nice enough to provide me with a beta version for testing. You can check out its official page here or you can follow the author on Twitter


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iOS Application Security Part 8 - Method Swizzling using Cycript

In the previous article, we looked at how we can install custom apps on our device without a developer certificate. In this article, we will look at how we can perform method Swizzling using Cycript on a sample application.

The first thing is to download the sample Xcode project. You can download the Xcode project from here. Or you can also just download the binary file on your device from here. If you have installed the Xcode project, you will have to build the Xcode project using a self signed certificate.The previous article talks about this in great detail. If you have downloaded the binary, you can directly run it on a jailbroken device without any issues but to get a look at the source code, it is recommended to download the Xcode project.

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iOS Application Security Part 7 - Installing and Running Custom Applications on Device without a registered developer account

Usually, to test apps on a device, you need to be a registered developer which costs about $99/year. For people who want to learn iOS Application security, it is very important that they should be able to run applications on device so that they can perfom tests on them. For some people who do not want to publish any apps on the app store, it may not be worth it to pay the $99/year fees. In this article we will be looking at how we can build and install an application on a jailbroken idevice without having a registered developer account. Then in the next article we will look at how we can run our own applications on the device and use Cycript to perform method swizzling and other techniques.

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iOS Application Security Part 6 - New Security Features in iOS 7

As we all know, Apple recently introducted its new version of iOS at WWDC 2013 with a completely redesinged User Interface. If you haven’t seen it yet, check out this video from WWDC 2013.

This article will be a small deviation from the other parts in this series. In this articles, we will discuss about the latest security features introduced in iOS 7.

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IOS 7 Beta 3 : Some bugs that i want Apple to Fix !

So i have had IOS 7 on my iPhone 5 since the day it was released at WWDC 2013. Since then, i have seen a number of bugs being fixed with the coming beta versions. However, there are some bugs that are still there, easily reproducible and not fixed yet !

The black Background bug.

To reproduce this, you need to have only one app running. Make sure you are on this app and double tap the home button.

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iOS Application security Part 5 – Advanced Runtime analysis and manipulation using Cycript (Yahoo Weather App)

In the previous article, we learnt how to setup Cycript on your idevice, hook into a running process and obtain information about its properties in runtime. In this article, we will look at some advanced runtime analysis techniques. We will look at how we can obtain information about a particular class (methods, instance variables) and modify them at runtime.

Finding methods for a particular class

Let’s say we are analyzing the flow of an app during its runtime. It would be really good to know what are the methods being called in a particular view controller or in a particular class. Since Cycript is a blend of Objective-C and Javascript, we can write a function that has both Objective-C and Javscript syntax. We can define functions in the interpreter and use them anytime we want to find out some particular information. A good source for finding such code snippets is available here and we will be using most of the code snippets from here for this article.

First of all, lets make sure we are hooked into the running process.


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iOS Appllication Security Part 4 – Runtime Analysis Using Cycript (Yahoo Weather App)

In the previous article, we learnt about the runtime capabilities of an iOS App written in Objective-C which uses the Cocoa framework. In this article, we will look at how we can use a very essential tool named Cycript to analyze and modify the runtime of an iOS application. In this article, we will be performing our analysis on the Yahoo Weather iOS app.


Cycript is a javascript interpreter which also understands Objective-C syntax, meaning we can write either Objective-C or javascript or even both in a particular command. It can also hook into a running process and help us to modify a lot of the things in the application during runtime. As far as its application to iOS application is concerned, here are some of the advantages of using Cycript.

  1. We can hook into a running process and find the names of all classes being used, i.e the view controllers, the internal and third party libraries being used and even the name of the Application delegate.
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Octopress: Category pages with preview and pagination

So i have been playing around with Octopress for a few weeks now and i love it. While creating this site, i bumped into a small problem.

How do i display a category page with a preview of all the blog posts and include pagination in it as well ?

Ofcourse, if you just want to visit the default category page that Octopress creates, you can just append something like /categories/[category_name]/ to the base url. For e.g here is the link to the posts with the category security. But this is so boring. It would have been cool to have a preview of each post just like the home page, and that also had pagination, something like this .

Here is how i did it.

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Pagination in Restkit 0.2 using RKPaginator

Restkit 0.2 supports pagination through a class called RKPaginator. It has all the necessary methods for supporting pagination properly and efficiently.

The first step is to define the properties required for pagination.

//Properties required for pagination
@property (nonatomic,strong) RKPaginator *paginator;
@property (nonatomic,strong) NSMutableArray *objects;
@property (nonatomic,assign) BOOL isPaginatorLoading;

Also make sure to define the url path for your request. The parameters after : denotes the attributes of the RKPaginator object. For e.g, in the below path, instead of :currentPage, the value that will be passed is the currentPage attribute of the paginator object. The two attributes that are necessarily required are perPage and currentPage.

#define kUrlStringForPagination @"/ios-pagination/?dummy_variable=dummyVariable&page=:currentPage&per_page=:perPage&dummy_variable2=dummyVariable2"
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