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[edso <1520691@xxxxxxxxxxxxxxxxxx>]

On 02.12.2015 17:48, Bernd Dietzel wrote:
> Ok, found why it not works.
> The character "/" ist automatically added at the end, so it results in "--log-file=xxx/" wtich wont work.
> If some valid parameter is at the end witch likes the "/" added, it works.
> In this Demo, i added "--partial-dir=/tmp" witch gets to "--partial-dir=/tmp/" witch i s valid.
> The xxx file was created in my home folder.
> 
> duplicity 'rsync://127.0.0.1/bug/ --log-file=xxx --partial-dir=/tmp'
> /home/Downloads/
> 
> So, when i use the rsync backend, any parameter witch allows to have a
> "/" at the end will be executed.
> 


whilst imperfect, i will not spend time fixing this obvious flaw. as i wrote, the same can be achieved "properly" by using --rsync-options. also using rsync plainly with these arguments would have an identical result.

the only way to fix this is to patch each and every backend and have it
shlex/pipes.quote() each and every string we use in the cmd line. but
until i see a vulnerability springing from this issue i am not going to
invest the effort, speaking only for myself here of course ;)

..ede/duply

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https://bugs.launchpad.net/bugs/1520691

Title:
   Shell Code Injection in hsi backend

Status in Duplicity:
  Fix Committed

Bug description:
  https://bugs.launchpad.net/ubuntu/+source/duplicity/+bug/1519103

  The "hsi" backend of duplicity is vulnerabe to code injections.

  It uses os.popen3() with should be replaced with subprocess.Popen().

  Thank you.

  File :
  -------
  /usr/lib/python2.7/dist-packages/duplicity/backends/hsibackend.py

  This is the function witch is vulnerable :
  ------------------------------------------------------------
      def _list(self):
          commandline = '%s "ls -l %s"' % (hsi_command, self.remote_dir)
          l = os.popen3(commandline)[2].readlines()[3:]

  Exploit Demo :
  ============

  On the Terminal type in :

  $ duplicity 'hsi://bug/";xeyes;"/test/' /tmp/bug

  --> This will start the program xeyes , but should not.

  I attached a screenshot of the exploit demo.

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