Gray Hat Hacking, Second Edition, 2nd Edition

Chapter 10. Writing Linux Shellcode

In this chapter, we will cover various aspects of Linux shellcode.

• Basic Linux Shellcode

  • System Calls

  • Exit System Call

  • Setreuid System Call

  • Shell-Spawning Shellcode with execve

• Implementing Port-Binding Shellcode

  • Linux Socket Programming

  • Assembly Program to Establish a Socket

  • Test the Shellcode

• Implementing Reverse Connecting Shellcode

  • Reverse Connecting C Program

  • Reverse Connecting Assembly Program

• Encoding Shellcode

  • Simple XOR Encoding

  • Structure of Encoded Shellcode

  • JMP/CALL XOR Decoder Example

  • FNSTENV XOR Example

  • Putting It All Together

• Automating Shellcode Generation with Metasploit

In the previous chapters, we used Aleph1’s ubiquitous shellcode. In this chapter, we will learn to write our own. Although the previously shown ...