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WIP - Metasploit & Ruby

Exploiting vulnerable applications with Ruby, as well as creating and editing Metasploit modules.

Installation and Fundamentals

Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. Elegant syntax, natural to read and easy to write.

  • Use Ruby as a multi-paradigm language that supports a functional style of programming.

  • You can use high order programming methodology and lambda calculus.

Installation

Getting started

Ruby from the command line

c:\Ruby193>ruby -e "puts 'Hello friend'"

Interactive Ruby

Classic default prompt prints more information than the simple one:

c:\Ruby193>irb --simple-prompt

Check Ruby interpreter

$ which ruby
/usr/bin/ruby

So use in your scripts #!/usr/bin/ruby as a shebang.

#!/usr/bin/ruby

puts 'Hi!'

For Windows machines, the easiest way to perform the same task is to associate the Ruby files using the Ruby installer.

The Power of Ruby

We'll cover two interesting examples which will be useful to explain the full potential of Ruby

  • irb: interactive ruby console.

  • Ruby One Liners: small programs that are defined with a single line of code, they are executed using the command line Ruby, they are often used for file/directory manipulation or simple file system scripting.

    • Some examples are:

      • File spacing

      • Numbering and calculations

      • Text Conversion or Substitution

cat unix command in Ruby oneliner

$ ruby -pe 0 'file'

  • -e: executes one line of ruby command.

  • -p: iterates into a loop that reads each line and prints them to stdout.

  • -pe 0 'file': read 'file' line to line and prints then to stdout, executing 0 command.

wc unix command in Ruby onliner

$ ruby -ne 'END {print "Lines:",$.,"\n"}' file

  • -e: executes one line of Ruby code between single quotes.

  • -n: puts the code into a loop.

  • print: prints the following string to stdout without adding a new line at the end.

  • END: executes the next block of instructions.

  • $.: global variable that holds the last line number read by ruby interpreter.

  • .: used to concatenate strings.

Replace substrings with Ruby oneliner

$ ruby -i.bak -pe 'gsub "foo","FOO"' file_name

  • -i: specifies in-place edit mode, making a backup of the original file.

  • gsub: global substitution.

Libraries

There are different sources of libraries, but the most uses is the packaging system RubyGems, which comes preinstalled with Ruby since version 1.9.

# Check documentation
gem help

# Search command used to look for gems
gem search <gem>

# Search for HTTP related remote gems
gem search -r http # -r: remote

# Search help options
gem search -h

# Help for install
gem install -h

# List your local installed gems
gem list

pry

The pry library provides an interactive environment with many interesting features such as syntax highlighting.

gem install pry

# Use the prompt you prefer
pry --simple-prompt

Network and OS Interaction

Network and OS Interaction

Ruby

The Web

The Web

Exploitation with Ruby

Exploitation with Ruby

Metasploit

Metasploit - Study Guide

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