Protostar – stack7

Information Stack6 introduces return to .text to gain code execution. The metasploit tool “msfelfscan” can make searching for suitable instructions very easy, otherwise looking through objdump output will suffice. This level is at /opt/protostar/bin/stack7 Source code Solution Well, I don’t understand the point of this level. It is exactly the same as the previous one. ...

Protostar – stack6

Information Stack6 looks at what happens when you have restrictions on the return address. This level can be done in a couple of ways, such as finding the duplicate of the payload (objdump -s) will help with this), or ret2libc, or even return orientated programming. It is strongly suggested you experiment with multiple ways of ...

Protostar – stack5

Information Stack5 is a standard buffer overflow, this time introducing shellcode. This level is at /opt/protostar/bin/stack5 Hints • At this point in time, it might be easier to use someone elses shellcode • If debugging the shellcode, use xcc (int3) to stop the program executing and return to the debugger • remove the int3s once ...

Protostar – stack4

Information Stack4 takes a look at overwriting saved EIP and standard buffer overflows. This level is at /opt/protostar/bin/stack4 Hints • A variety of introductory papers into buffer overflows may help. • gdb lets you do “run < input” • EIP is not directly after the end of buffer, compiler padding can also increase the size. ...

Protostar – stack3

Information Stack3 looks at environment variables, and how they can be set, and overwriting function pointers stored on the stack (as a prelude to overwriting the saved EIP) Hints • both gdb and objdump is your friend you determining where the win() function lies in memory. This level is at /opt/protostar/bin/stack3 Source code Solution After ...

Protostar – stack2

Information Stack2 looks at environment variables, and how they can be set. This level is at /opt/protostar/bin/stack2 Source code Solution In this challenge again, the vulnerability is located at the line : strcpy(buffer, variable); Instead of the argv[1] value, it is the value of ‘variable’ which is copied in ‘buffer’. ‘variable’ is equal to the ...

Protostar – stack1

Information This level looks at the concept of modifying variables to specific values in the program, and how the variables are laid out in memory. This level is at /opt/protostar/bin/stack1 Hints • If you are unfamiliar with the hexadecimal being displayed, “man ascii” is your friend. • Protostar is little endian Source code Solution The ...

Protostar – stack0

Information This level introduces the concept that memory can be accessed outside of its allocated region, how the stack variables are laid out, and that modifying outside of the allocated memory can modify program execution. This level is at /opt/protostar/bin/stack0 Source code Solution Alright, let’s start this new set of challenges !! After having looked ...