20+ Ways to Bypass Your macOS Privacy Mechanisms

Presented at Black Hat USA 2021, Aug. 4, 2021, 10:20 a.m. (40 minutes).

"TotallyNotAVirus.app" would like to access the camera and spy on you. To protect your privacy, Apple introduced Transparency, Consent, and Control (TCC) framework that restricts access to sensitive personal resources: documents, camera, microphone, emails, and more. Granting such access requires authorization, and the mechanism's main design concern was clear user consent.

In this talk, we will share multiple techniques that allowed us to bypass this prompt, and as a malicious application, get access to protected resources without any additional privileges or user's consent. Together, we submitted over 40 vulnerabilities just to Apple through the past year, which allowed us to bypass some parts or the entire TCC. We also found numerous vulnerabilities in third-party apps (including Firefox, Signal, and others), which allowed us to avoid the OS restrictions by leveraging the targeted apps' privileges.

In the first part of the talk, we will give you an overview of the TCC framework, its building blocks, and how it limits application access to private data. We will explore the various databases it uses and discuss the difference between user consent and user intent.

Next, we will go through various techniques and specific vulnerabilities that we used to bypass TCC. We will cover how we can use techniques like process injection, mounting, application behavior, or simple file searches to find vulnerabilities and gain access to the protected resources.

The audience will leave with a solid understanding of the macOS privacy restrictions framework (TCC) and its weaknesses. We believe there is a need to raise awareness on why OS protections are not 100% effective, and in the end, users have to be careful with installing software on their machines. Moreover - as we're going to publish several exploits - red teams will also benefit from the talk.


Presenters:

  • Wojciech Reguła - Senior IT Security Specialist, SecuRing
    Wojciech Reguła is a Senior IT Security Specialist working at SecuRing. He specializes in application security on Apple devices. He created the iOS Security Suite - an opensource anti-tampering framework, Bugcrowd MVP, found vulnerabilities in Apple, Facebook, Malwarebytes, Slack, Atlassian, and others. In his free time, he runs an infosec blog - https://wojciechregula.blog and shared research on among others Objective by the Sea (Hawaii, USA), AppSec Global (Tel Aviv, Israel), AppSec EU (London, United Kingdom), CONFidence (Cracow, Poland) and BSides (Warsaw, Poland).
  • Csaba Fitzl - Content Developer, Offensive Security
    Csaba Fitzl graduated in 2006 as a computer engineer. He worked for 6 years as a network engineer, troubleshooting and designing big networks. After that, he worked for 8 years as a blue and red teamer focusing on network forensics, malware analysis, adversary simulation, and defense bypasses. Currently, he is working as a content developer at Offensive Security. He gave talks/workshops at various international IT security conferences, including Hacktivity, hack.lu, Troopers, SecurityFest, DEFCON, and Objective By The Sea. Csaba spends his free time with his family, practices ashtanga yoga before sunrise, or hikes in the mountains.

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