Remote command execution in Ruby Gem Command Wrap

[Larry0 () me com]

Remote command execution in Ruby Gem Command Wrap

3/15/2013
http://rubygems.org/gems/command_wrap

Commands executed if the remote URL or filename contains the shell character ';'. The commands will be executed as the 
client user if tricked into using the malicious URL or filename.

Examining the following lines:

command_wrap.rb-7- def self.capture (url, target)

command_wrap.rb-8-        command = CommandWrap::Config::Xvfb.command(File.dirname(__FILE__) + "/../bin/CutyCapt 
--min-width=1024 --min-height=768 --url={url} --out={target}")
command_wrap.rb:9:        `#{command}`
command_wrap.rb-10- end
command_wrap.rb-11-
--
command_wrap.rb-72- command = CommandWrap::Config::Xvfb.command(File.dirname(__FILE__) + "/../bin/wkhtmltopdf --quiet 
--print-media-type #{source} #{params} #{target}") command_wrap.rb-73-
command_wrap.rb:74: `#{command}`

Untrusted data is passed to the command line.

Larry W. Cashdollar
@_larry0
http://vapid.dhs.org/advisories/command-wrap-remoteexec.html