Reversing is Fun
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Application code, file data, network protocol packets are often formatted as binary information. This is to protect intellectual property and make it difficult for attackers and competitors. This does not, however, stop security professionals, researchers andhobbysts to inspect and reverse the binary blobs. Either for understanding their internals, or for finding flaws, people do reversing on binary blobs and extract a human-friendly format. Andrew Tridgell famously reversed the CIFS/SMB protocol from Microsoft to create the Samba software. In this talk I will highlight the mindset for doing reversing, based on my own experience with reversint the Apple iOS sandbox. The talk is not meant to be very technical rather what it takes and what it means to do reversing and why you should do it as a learning and fun experience.
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Reversing is Fun
- 1. Reversing is Fun R˘azvan Deaconescu razvan.deaconescu@cs.pub.ro CompSoc, University of Leeds November 29, 2018 1 / 38
- 3. Me as a Breaker, Repairman, Improver pretty scared as a child didn’t break things on purpose but it happens 3 / 38
- 4. Wired Toy Car Hack https://bricks.stackexchange.com/questions/6755/ how-do-i-make-a-remote-control-car-without-lego-motors 4 / 38
- 5. Rambo Joystick Continuous Repairing https://www.digitiser2000.com/main-page/top-10-funny-console-knock-offs 5 / 38
- 8. Why? Why do kids break stuff? Why do people break stuff? 8 / 38
- 9. Why? (2) innate curiosity desire to look inside, to know how it works feels good when we know feels better when we repair achievement, accomplishment, improvement goal, purpose 9 / 38
- 10. Dan Pink: Drive https://www.amazon.co.uk/Drive-Daniel-H-Pink/dp/184767769X autonomy, mastery, purpose 10 / 38
- 11. Linus Torvalds and Linux https://www.amazon.co.uk/Just-Fun-Story-Accidental-Revolutionary/dp/0066620732 11 / 38
- 13. What is Reversing / Reverse Engineering? https://www.wisewhysofsales.com/2017/01/10/reverse-engineering-a-sale/ 13 / 38
- 15. Andrew Tridgell and Samba https://commons.wikimedia.org/wiki/File:Logo_Samba_Software.svg 15 / 38
- 16. Why Break Programs? https://null-byte.wonderhowto.com/how-to/ hacks-behind-cracking-part-1-bypass-software-registration-0132568/ know how they work for fun for fame and glory hackers, crackers, white/black hat, ethical 16 / 38
- 17. Public Hacking/Cracking https://www.blackhat.com https://www.defcon.org http://www.hitb.org 17 / 38
- 18. Is It Easy? 18 / 38
- 21. Is It Easy? http://www.ozpolitic.com/cgi-bin/album.pl?photo=forum-attachments/-hell-the-f-no.jpg 21 / 38
- 22. Reverse engineering can be depressing and quite solitary. The support from all of you @vu5ec was always there :-), I appreciate the encouragement that I got throughout the process. It was painfully fun! Lucian Cojocar Reversing is like catching a cobra by the back legs. R˘azvan Deaconescu 22 / 38
- 23. My Story CTF security contests (Capture the Flag) master classes on security (open content) https://ocw.cs.pub.ro/courses/cns http://elf.cs.pub.ro/sis/ security summer school (open content): https://security.cs.pub.ro/summer-school/wiki/ 23 / 38
- 24. My Story in iOS Reversing https://developer.apple.com/library/archive/documentation/Security/Conceptual/ AppSandboxDesignGuide/AboutAppSandbox/AboutAppSandbox.html 24 / 38
- 25. Sandboxing limit actions for processes / applications; i.e. open a file, connect to a remote host in iOS, there are sandbox profiles attached to applications a sandbox profile contains a specific set of rules container sandbox profile used for all 3rd party apps (i.e. those installed from Apple AppStore) 25 / 38
- 26. Initial Format of iOS Sandbox Profiles (version 1) (allow default) (deny network* (local ip "*:*")) (deny network-outbound (literal "/private/var/tmp/launchd/sock") (regex #"^/private/tmp/launchd-[0-9]+[.][^/]+/")) 26 / 38
- 27. Deployed Format of iOS Sandbox Profiles 00000000: 0080 5c9c 9f00 849c 0300 8c00 859c 0000 00000010: 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c 00000020: 5b9c 5b9c 579c fe9b 5a9c f39b 5b9c 5b9c 00000030: 5b9c 959b 939b 6b9b 959b 5b9c 5b9c 5b9c 00000040: 4f9b 4f9b 4f9b 459b 4f9b 439b 4f9b 4f9b 00000050: 4f9b 4f9b 359b 5b9c 5b9c 5b9c 5b9c 5b9c 00000060: 5b9c 5b9c 5b9c 5b9c 349b 5b9c 5a9c 5b9c 00000070: 5b9c 5b9c 5b9c 5b9c 339b 5b9c 5b9c 5b9c 00000080: 329b 309b 309b 309b 329b 329b 2f9b 2f9b 00000090: 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c 5b9c [...] 27 / 38
- 28. Reversing the iOS Sandbox https://coryseznec.bandcamp.com/track/sisyphus SandBlaster https://arxiv.org/abs/1608.04303 https://github.com/malus-security/sandblaster 28 / 38
- 29. The Journey close to an year to get it working another half year to make it work on almost all cases relentless back-and-forth made it open source relied on previous work (Dionysus Blazakis, Stefan Esser, Dino Dai Zovi) 29 / 38
- 30. Yes but . . . . . . it seems daunting . . . it takes time 30 / 38
- 31. However . . . it will be fun you will improve: patience, perseverance, lateral thinking, problem solving you are part of a community 31 / 38
- 32. What To Do? CTF contents https://picoctf.com https://junior.35c3ctf.ccc.ac/announcements/ https://ctftime.org http://captf.com/practice-ctf/ wargames http://io.netgarage.org http://smashthestack.org/wargames.html http://overthewire.org/wargames/ 32 / 38
- 33. Professional Reverse Engineers fame, glory money training note legal aspects responsible disclosure 33 / 38
- 34. Yeah, but ... I’m more of a developer I want to build stuff, not break stuff I want to create 34 / 38
- 35. Perspective Sergiu Weisz, 1st year master student I want to build. But I choose to do security because it gives me a better understanding of how things work. And how things can be attacked, abused and brought down. poorly built software, hardware and infrastructure you can make it better, more secure, more robust once you understand it’s inner working 35 / 38
- 36. Build it. Break it. Make it better. 36 / 38
- 37. Resources mine slides: https://www.slideshare.net/razvandeaconescu/ https://ocw.cs.pub.ro/courses/cns http://elf.cs.pub.ro/sis/ https://security.cs.pub.ro/summer-school/wiki/ https://arxiv.org/abs/1608.04303 https://github.com/malus-security/sandblaster conferences, events, magazines https://www.blackhat.com https://www.defcon.org http://www.hitb.org http://phrack.org/ 37 / 38