dragons_ctf

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Getting remote shell • Otherwise, it’s more complicated. – Even if the executable doesn’t import system() specifically, it almost always imports a number of other functions. – The low 12 bits of their addresses are constant: they are offsets within memory pages and thus not subject to ASLR. – These offsets are characteristic for specific versions of libc!
Creating a corpus of libc files • Download all available libc images for common distros. – Ubuntu and Debian are typically used to host CTF challenges. • Process them with objdump to extract addresses of all public symbols. • ??? • PROFIT!
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Pwning (sometimes) with style Drago
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Dragon Sector? Insomni'hack 2014 Ge
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Agenda
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The SSP leak • Stack Smashing Pro
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SSP basics - canary verification
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__stack_chk_fail *** stack smashing
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__stack_chk_fail void __attribute__
Page 15 and 16: The argv array is at the top of the
Page 17 and 18: We can overwrite it, too! $ ./test_
Page 19 and 20: Very powerful memory disclosure •
Page 21: References 1. Dan Rosenberg, Fun wi
Page 24 and 25: Remote KG Task: Given a PCAP file,
Page 26 and 27: Remote KG So… what is this protoc
Page 28 and 29: Remote KG Next steps: ● write a p
Page 30: JS Puzzle Event: Organizers: SECCON
Page 34 and 35: One-gadget RCE on Linux • Assumin
Page 36 and 37: One-gadget RCE on Linux • An exec
Page 38 and 39: One-gadget RCE on Linux If std{out,
Page 40 and 41: I/O redirection /bin/sh &N • By d
Page 42 and 43: One-gadget RCE on Windows • In GN
Page 44 and 45: One-gadget RCE on Windows • There
Page 46: LoadLibrary(“\\11.22.33.44\payloa
Page 49 and 50: zfs Problem 1: Nothing wants to mou
Page 52 and 53: zfs ● xor_key ● key.xor_encrypt
Page 54 and 55: zfs ● Gynvael’s way: Brute forc
Page 56 and 57: zfs Minimizing input - assume that
Page 58 and 59: zfs
Page 60 and 61: zfs
Page 64 and 65: And about system()… • How do we
Page 68 and 69: With this, we can… • Leak the a
Page 70 and 71: libcdb.com
Page 72 and 73: There’s another way, too • If w
Page 74: Other teams do it, as well Quote fr
Page 77 and 78: World Wide Something ^_- TL;DR: .pc
Page 79 and 80: World Wide Something ^_- Let's recr
Page 82 and 83: ROP gadgets near libc imports • E
Page 84 and 85: ROP gadgets near libc imports • 1
Page 86 and 87: ROP gadgets near libc imports • S
Page 88 and 89: Partial .got.plt overwrites • If
Page 90: Brute-forcing ASLR • ASLR on popu
Page 94 and 95: Format String Fun Typical exploitat
Page 96 and 97: Even More Format String Fun! Assume
Page 98 and 99: Even More Format String Fun! printf
Page 101 and 102: Getting read / recv to fail Imagine
Page 103 and 104: One-sided connection termination
Page 105: One-sided connection termination By
Page 108 and 109: Mumble Mumble high entropy
Page 110 and 111: Mumble Mumble Approach change: 1. A
Page 112 and 113: Mumble Mumble
Page 114 and 115: Mumble Mumble ...- -... .-. -- -.--
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Patching vs instrumentation ● ●
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0x90 Event: SIGINT CTF 2013 Organiz
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0x90 • We decided to run the bina
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It worked! Bochs log console
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Conclusions • CTFs are really fun
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