virtualenv Sandbox escape

[BakedPotato999]

Exploit Title: virtualenv Sandbox escape
Date: 2018-9-30
Exploit Author: Topsec Technologies Inc. - vr_system
Version: 16.0.0
Tested on: kali linux
CVE : None

root@kali:~#pip install virtualenv
root@kali:~#virtualenv test_env
root@kali:~#cd test_env/
root@kali:~/test_env#source ./bin/activate
(test_env) root@kali:~/test_env#`
`2、Sandbox escape
(test_env) root@kali:~/test_env#python $(bash >&2)
root@kali:~#
(test_env) root@kali:~/test_env#python $(rbash >&2)
root@kali:~#```

[fgeek]

CVE-2018-17793 has been assigned to this issue (not requested by me).

[Brcrwilliams]

Could you please explain the security impact here? Calling bash to get back to the normal shell does not seem like a vulnerability to me. I do not think that anyone was under the impression that virtualenv allows you to safely run untrusted shell commands, that is not what it is for.

[jsegitz]

I asked MITRE to reject the CVE

[BakedPotato999]

Normal as follows:
(test_env) r0ot#python $(sh 1>&2)
(test_env) r0ot#
(test_env) r0ot#python
Python 2.7.15 (default, May 1 2018, 05:55:50)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.

import os
os.system("$(sh 1>&2)")
(test_env) r0ot#
If you execute malicious code:
(test_env) r0ot#python $(bash >&2)
r0ot#
POC:
(test_env) r0ot#python
Python 2.7.15 (default, May 1 2018, 05:55:50)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import os
os.system("$(bash >&2)")
r0ot#

[Brcrwilliams]

If you execute malicious code

Yes, and if you jump off a building you might hit something on the way down. It doesn't really matter since you're already in big trouble from jumping to begin with.

[BakedPotato999]

PYTHON in the sandbox is not 100% secure, and vulnerabilities can result in bypassing the sandbox protection. What are the reasons for using the sandbox?
If the sandbox is difficult to fix, it is recommended to avoid risk in the code and be prompted in the sandbox description.

[0cjs]

@BakedPotato999 Python in the virtualenv "sandbox" is 0% secure; it's neither designed to nor does it provide any protection against malicious code. You seem very confused about the purpose of virtualenv.

[BakedPotato999]

@BakedPotato999 Python in the virtualenv "sandbox" is 0% secure; it's neither designed to nor does it provide any protection against malicious code. You seem very confused about the purpose of virtualenv.

I think the applications running in this Virtualenv are independent and will not affect your existing operating system. Closing the sandbox will restore all operations. With the sandbox, you can test programs and software that might be risky. Is that right?

[0cjs]

Nope, completely wrong. The purpose of a virtualenv is to let you use a specific Python interpreter and set of Python packages (instead of the system- and userdir-installed packages) to run programs in an otherwise normal environment.

The "sandbox," such as it is, should by default not include system and user packages, just the ones installed in the virtualenv. But there's nothing stopping you from, e.g., changing sys.path to bring back in default system or user packages.

Nor should anything stop you from doing that. The Python interpreter in a virtualenv should be able to do all operations that the system Python interpreter (if any) can do when run by the same user. To do otherwise would break many common and expected uses of a virtualenv.

[zoidyzoidzoid]

@BakedPotato999 virtualenv/bin/activate basically just puts the Python executable in the virtual environment earlier in your path. It's not built for security.

[gaborbernat]

I'll close this as invalid.

[disconnect3d]

I just wonder, how did you come with virtualenv being a sandbox @BakedPotato999 ?

I searched through docs, github and with a git grep and the only sandbox occurence is this one:

James Gardner has written a tutorial on using virtualenv with Pylons.

which links to http://wiki.pylonshq.com/display/pylonscookbook/Using+a+Virtualenv+Sandbox (which has sandbox in the url).

By the way, the url is dead and it is here https://github.com/pypa/virtualenv/blob/384c8d13490f171a7ad99eeedd7fe45021a83d87/docs/index.rst

;).

[offlinehacker]

The fact that there exists "exploit" now https://www.exploit-db.com/exploits/45528/ and that security trackers of major distros treat this as vulunerability is rather funny.