The Importance of Using Bitfields in X and U

We've got a pretty nice root/super-use check bypass in XNU this week, and a sort of double fetch issue in Intel's SMM leading to a potential privilege escalation into the Management system. We've also got a few meme-able Shannon Baseband issues and some tough to exploit out of bound reads in MIT Kerberos V5.

Links and vulnerability summaries for this episode are available at: https://dayzerosec.com/podcast/198.html

[00:00:00] Introduction

[00:00:27] Spot the Vuln - The Right Context

[00:02:52] Discussion: Using GPT-4 to Spot Vulnerabilities in Code (and SecGPT)

[00:11:05] A Race to Report a TOCTOU: Analysis of a Bug Collision in Intel SMM

[00:19:32] Out-of-Bounds Read in the MIT Kerberos V5 (krb5) library

[00:25:35] XNU: NFSSVC root check bypass; use after free due to insufficient locking in upcall worker threads

[00:32:36] XNU: NFSSVC root check bypass; use after free due to insufficient locking in upcall worker threads

[00:36:35] Shannon Baseband: Intra-object overflow in NrmmMsgCodec when decoding Service Area List

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