Brida is a Burp Suite Extension that, working as a bridge between Burp Suite and Frida, lets you use and manipulate applications’ own methods while tampering the traffic exchanged between the applications and their back-end services/servers. It supports all platforms supported by Frida (Windows, macOS, Linux, iOS, Android, and QNX).
This idea is a need that is born during the analysis of some mobile application that use strong symmetric cryptography using random keys, without knowing the correct secret all data was not modifiable via Burp neither with a custom plugin. More generally, applications' logic could be based on cryptographic tokens, it could use a complex challenge-response algorithm as well, and so on. How can we tamper the messages? Most of the times the only viable approach is to decompile/disassemble the application, identify the functions or methods we’re interested in AND re-implement them. This approach is obviously time consuming and not always really viable: i.e. the generation of tokens and/or the encryption routines could be based on cryptographic material strictly tied to the device (state) or stored inside protected areas and thus not directly accessible... That’s when Brida comes in handy: instead of trying to extract keys/certificates and re-writing the routines we’re interested in, why don’t we let the application do the dirty work for us?
Short answer is everyone!
Long answer is that Brida is a collection of tools, some of them created to speed-up everyday mobile assessments and to help new Frida users, while others aimed at addressing very complex situations, in which Brida can really make the difference.
Tools that can be valuable to handle and speed-up everyday mobile assessments are the following ones:
- Many Frida hooks for common tasks, directly callable from the GUI of the tool. These scripts include the most recent hooks for Android and iOS platforms to bypass and inspect security features
- An analysis tab, in which you have a tree representation of the binary (Java/OBJC classes and methods, imports/exports) and from which you can graphically add inspection hooks (that print arguments and return value every time that the hooked function is executed) and tamper hooks (that dynamically change the return value of the hooked function every time that it is executed)
- An integrated JS editor with JavaScript syntax highlighting, in order to be able to add your own Frida exports and Frida hooks directly from Burp Suite
However, the idea that led to Brida creation was to help pentesters/reversers/hackers to analyze the webservices of target mobile applications where complex security features are in place to protect the confidentiality and integrity of the HTTP requests and responses. Encryption, obfuscation, signatures routines executed on requests and responses can make the work on testers very difficult and time-consuming, because usually it is necessary to reverse the security mechanisms and to implement a Burp Suite plugin or an external tool that first decrypt/de-obfuscate the HTTP messages and then eventually encrypt/obfuscate/sign edited messages. The same applies also to some non-security scenarios, like for example if a custom binary protocol is used to format the body of HTTP requests/responses for interoperability or performance purposes.
Brida tries to speed-up those procedures as much as possible, by limiting the reversing effort and by completely removing (in most situations) the developing one, by offering an engine that allows to graphically create custom plugins that inspect and edit HTTP requests and responses using the same mobile functions used by the mobile application itself, thanks to Frida. Taking as an example a mobile application that encrypt/decrypt all the requests and responses with a custom/unknown encryption algorithm, Brida allows to graphically create a simple custom plugin that decrypt the encrypted HTTP messages using directly the mobile code used by the mobile application to do the job. Another example can be a custom plugin that transparently update signatures of signed HTTP requests when are sent to the backend using the same mobile functionality used by the application itself.
More in detail, Brida allows to graphically create the plugins that:
- Process requests/responses that pass through every Burp Suite tool, in order to be able to encrypt/decrypt/resign elements of requests and responses using Frida exported functions
- Add custom tab to Burp Suite request/response pane, in order to be able to decrypt/decode/process requests/responses (or portion of them) using Frida exported functions (and then encrypt/encode/process modifications and replacing the original request/response, if any)
- Add custom context menu options to invoke Frida exported functions on requests and responses
- Add buttons that invoke/enable Frida exported functions
And if Brida custom plugin engine is not enough for our super-complex situations, it is also possible to write external Python/Java Burp Suite extensions that leave to Brida the task of executing the functions of the target mobile application on the data of the extension. Brida "Generate Stubs" tool generates the Java or Python code that can be pasted in external Python or Java extensions to use the Brida bridge.
In order to be able to use Brida, you need:
- Burp Suite (1.X or 2.X)
- Frida client
- Pyro4
- frida-compile (!!! use version 10.2.5, last version of frida-compile do not work at the moment, debug in progress... !!!)
- A jailbroken iOS device/rooted Android device with frida-server running on it (or an application patched with the frida-gadget)
- An application to analyze! :D
- Install Python 2.7 or Python 3, Pyro4 (pip install pyro4) and frida (pip install frida). python virtual environments are fully supported.
- Install Node.js, npm and frida-compile (npm install frida-compile@9). At the moment there are issues with version 10 of frida-compile, but we are trying to solve them.
- Download Burp Suite: http://portswigger.net/burp/download.html
- Download the last release of Brida: https://github.com/federicodotta/Brida/releases
- Open Burp -> Extender -> Extensions -> Add -> Choose BridaXX.jar file
- Install Python 2.7 or Python 3, Pyro4 (pip install pyro4) and frida (pip install frida). python virtual environments are fully supported.
- Install Node.js, npm and frida-compile (npm install frida-compile@10.2.5). At the moment there are issues with version 10 of frida-compile, but we are trying to solve them.
- Download Burp Suite: http://portswigger.net/burp/download.html
- Open Burp -> Extender -> BApp Store -> Brida, Burp to Frida bridge -> Install
You can build Brida using Maven. Brida uses a modified version of RSyntaxTextArea, that you can find in this fork. In order to be able to build Brida you have to download the last release of the modified version of RSyntaxTextArea or build it and then install it locally with Maven using the following parameters:
- groupId: com.fifesoft
- artifactId: rsyntaxtextarea
- version: 2.6.1.edited
Installation and usage notes can be found in the Wiki page.
The slides of our conference presented at HackInBo 2017 Winter Edition that describes the first version can be found at:
The slides and the video of our conference presented at Hack In The Box 2018 Amsterdam that describes the new features of the version 0.2 can be found at:
- (ENG) https://conference.hitb.org/hitbsecconf2018ams/materials/D1T1%20-%20Federico%20Dotta%20and%20Piergiovanni%20Cipolloni%20-%20Brida%20When%20Burp%20Suite%20Meets%20Frida.pdf
- (ENG) https://www.youtube.com/watch?v=wPepicuHDzs&t=18s
The video of our conference presented at Hack In Paris 2020 2021 (postponed for the COVID-19 global situation) that describes the new features of the version 0.4 0.5 can be found at:
Two different demo applications can be found in the Demo folder, one Android and one iOS.
The demo folder contains also the Brida plugins that can be used to bypass the encryption mechanisms used by the apps!
- Federico Dotta, Principal Security Analyst at HN Security
- Piergiovanni Cipolloni, Principal Security Analyst at HN Security
- Maurizio Agazzini
Brida uses a lot of Frida code for dynamic hooking and for binary inspection, based on the work of:
- Marco Ivaldi
- Maurizio Agazzini
- Luca Baggio
- Federico Dotta
Furthermore, Brida integrates many Frida hooks developed by various authors to inspect/bypass many security features. A list of projects (I hope quite exhaustive) from which I took Frida code for the "Hooks and functions" section of Brida is (random order):
- Piergiovanni Cipolloni - Universal Android SSL Pinning Bypass with Frida
- Mattia Vinci and Maurizio Agazzini - Universal Android SSL Pinning Bypass 2
- Maurizio Siddu - frida-multiple-unpinning
- dzonerzy - fridantiroot
- F-Secure Labs - Android KeyStore Audit
- F-Secure Labs - needle
- Alban Diquet - SSL Kill Switch 2
- dki - ios10-ssl-bypass
- macho_reverser - iOS 12 SSL Bypass
- Chaitin Tech - Passionfruit
- lich0 - dump ios
- ay-kay - iOS DataProtection
- neil-wu - FridaSwiftDump
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