2021-04-22

[public] 118K views, 9.8K likes, 38.0 dislikes audio only

LiveOverflow

The most comprehensive video covering the sudo vulnerability CVE-2021-3156 Baron Samedit. I spent two weeks on rediscovering, analysing and exploitation of the sudoedit heap overflow. We will talk about fuzzing, code review, exploit strategies, heap feng shui and developing the exploit.

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Article: https://liveoverflow.com/critical-sudo-vulnerability-walkthrough-cve-2021-3156/

Binary Exploitation Playlist: https://www.youtube.com/playlist?list=PLhixgUqwRTjxglIswKp9mpkfPNfHkzyeN

PwnFunction's Binary Exploitation Playlist: https://www.youtube.com/playlist?list=PLI_rLWXMqpSkAYfar0HRA7lykydwmRY_2

Full CVE-2021-3156 Advisory: https://packetstormsecurity.com/files/161160/Sudo-Heap-Based-Buffer-Overflow.html

Qualys Blog: https://blog.qualys.com/vulnerabilities-research/2021/01/26/cve-2021-3156-heap-based-buffer-overflow-in-sudo-baron-samedit

milek7's blog on fuzzing sudo: https://milek7.pl/howlongsudofuzz/

00:00 - Intro and Motivation

01:33 - afl: Fuzzing argv[]

03:22 - afl: sudo vs. sudoedit

04:27 - afl: Fuzzing setuid Process

06:49 - Fuzzing Conclusion

07:11 - Code Review: Identify Risky Code Through Isolation

09:39 - Code Review: Bypass Safe Conditions

11:15 - Exploit Strategy: Modern Mitigations

12:25 - The service_user Object Overwrite Technique

13:48 - Heap Feng Shui via Environment Variables

14:57 - Bruteforce Script to Find Exploitable Conditions

15:39 - Find and Analyse Useful Crashes

16:31 - Exploitability Analysis Conclusion

17:13 - Qualys Researchers Knew nss From Stack Clash

17:47 - Sudoedit Exploitable on macOs?

18:32 - Research Conclusion

19:27 - Outro

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