Lemmy: Bestiverse
  • Communities
  • Create Post
  • Create Community
  • heart
    Support Lemmy
  • search
    Search
  • Login
  • Sign Up
RSS BotMB to Hacker NewsEnglish · 2 hours ago

Modern iOS Security Features – A Deep Dive into SPTM, TXM, and Exclaves

arxiv.org

external-link
message-square
0
fedilink
2
external-link

Modern iOS Security Features – A Deep Dive into SPTM, TXM, and Exclaves

arxiv.org

RSS BotMB to Hacker NewsEnglish · 2 hours ago
message-square
0
fedilink
Modern iOS Security Features -- A Deep Dive into SPTM, TXM, and Exclaves
arxiv.org
external-link
The XNU kernel is the basis of Apple's operating systems. Although labeled as a hybrid kernel, it is found to generally operate in a monolithic manner by defining a single privileged trust zone in which all system functionality resides. This has security implications, as a kernel compromise has immediate and significant effects on the entire system. Over the past few years, Apple has taken steps towards a more compartmentalized kernel architecture and a more microkernel-like design. To date, there has been no scientific discussion of SPTM and related security mechanisms. Therefore, the understanding of the system and the underlying security mechanisms is minimal. In this paper, we provide a comprehensive analysis of new security mechanisms and their interplay, and create the first conclusive writeup considering all current mitigations. SPTM acts as the sole authority regarding memory retyping. Our analysis reveals that, through SPTM domains based on frame retyping and memory mapping rule sets, SPTM introduces domains of trust into the system, effectively gapping different functionalities from one another. Gapped functionality includes the TXM, responsible for code signing and entitlement verification. We further demonstrate how this introduction lays the groundwork for the most recent security feature of Exclaves, and conduct an in-depth analysis of its communication mechanisms. We discover multifold ways of communication, most notably xnuproxy as a secure world request handler, and the Tightbeam IPC framework. The architecture changes are found to increase system security, with key and sensitive components being moved out of XNU's direct reach. This also provides additional security guarantees in the event of a kernel compromise, which is no longer an immediate threat at the highest trust level.

Comments

alert-triangle
You must log in or register to comment.

Hacker News

hackernews

Subscribe from Remote Instance

You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !hackernews@lemmy.bestiver.se
lock
Community locked: only moderators can create posts. You can still comment on posts.

Posts from the RSS Feed of HackerNews.

The feed sometimes contains ads and posts that have been removed by the mod team at HN.

Visibility: Public
globe

This community can be federated to other instances and be posted/commented in by their users.

  • 406 users / day
  • 1.71K users / week
  • 3.9K users / month
  • 9.59K users / 6 months
  • 2 local subscribers
  • 2.8K subscribers
  • 33.5K Posts
  • 14.3K Comments
  • Modlog
  • mods:
  • patrick
  • RSS Bot
  • BE: 0.19.5
  • Modlog
  • Instances
  • Docs
  • Code
  • join-lemmy.org