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Buffer Overflow Attacks

The document is an introduction to buffer overflow attacks, emphasizing the risks and legal implications of hacking. It covers technical aspects such as stack smashing, function call arrangements, and includes practical examples and demonstrations without promoting illegal activities. The presentation also acknowledges various security resources and platforms for further learning.

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Buffer Overflow Attacks A humble introduction
$whoami • Security Enthusiast with an interest in knowing things inside out.
DISCLAIMER Without rwx-r-x-r • Breaking software is ILLEGAL • Hacking into networks is ILLEGAL • Launching worms/virus attacks is ILLEGAL • Governed by Indian Law - Information Technology Act, 2000. • Section 65/66/66A…F/67 etc. • This ppt is only for demo purposes and I am in no way responsible for any damage done through this knowledge to self or otherwise.
What is it about? • Buffer overflow • Stack smashing
Don’t Expect • Tool internals • Tool tutorials • Tool specifications • Social engineering techniques • Exploit/Payload writing
Live Attack Demo • Real life attacks are actually REAL ! • Vulnerable Unzip Utility • Impact • What do you loose if you are “NAIVE”
Some useful basics? • ESP, EIP • Return address • EBP • Environment - 32bit Ubuntu 15 - ASLR disabled and gcc - stack smashing protection - disabled.
Function call and stack arrangement ? • ESP, EIP • Return address • EBP • funcall.c • funCall gdb analysis
GOAL • Control execution flow • How ? • Control EIP • Where ? • Control it in the stack (for stack smashing) • Why ? • User input makes it’s way to the buffers in the stack • CALL and RET instruction auto-handle what goes in the EIP
writing exit shell code • justQuit.c • disassemble justQuit and figure out _exit • exitInAsm.s • objdump exitInAsm to get the shell code
using the exit shell code • exitShellCode.c • exitShellCode gdb analysis
attacker-vicim demo • actual shell code - spawning a shell • check in exitShellCode.c • attack crafting concept • default address to anything • gdb analysis - address change and exploit
The $M ? “Who & Why” • Several flaws in VLC • GHOST in glibc • getaddrinfo in glibc • Several flaws in Apache/IIS/nginx • All of this for FUN and PROFIT.
HUGE Thanks • Security Tube • Numerous blogs • StackOverflow • Null.co.in • SecurityXploded • Sans.org • LinuxFoundation.org