Bug 1631420 – CVE-2018-1000802 python: Command injection in the shutil module

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Bug 1631420 - (CVE-2018-1000802) CVE-2018-1000802 python: Command injection in the shutil module

Summary:	CVE-2018-1000802 python: Command injection in the shutil module

Status:	CLOSED NOTABUG

Aliases:	CVE-2018-1000802

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
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URL:
Whiteboard:	impact=moderate,public=20180829,repor...
Keywords:	Security

Depends On:	1631421 1631662
Blocks:	1631422
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Reported:	2018-09-20 10:32 EDT by Andrej Nemec
Modified:	2018-10-24 11:46 EDT (History)
CC List:	19 users (show)

See Also:
Fixed In Version:
Doc Type:	If docs needed, set a value
Doc Text:	It was discovered that the shutil module of python does not properly sanitize input when creating a zip file on Windows. An attacker could use this flaw to cause a denial of service or add unintended files to the generated archive.
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Last Closed:	2018-10-10 03:33:46 EDT
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Regression:	---
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Documentation:	---
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RHEL 7.3 requirements from Atomic Host:
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Description Andrej Nemec 2018-09-20 10:32:08 EDT

A command injection vulnerability was found in the shutil module (make_archive function) of Python that can result in Denial of Service or Information leak.

Upstream issue:

https://bugs.python.org/issue34540

Upstream patch:

https://github.com/python/cpython/pull/8985/commits/add531a1e55b0a739b0f42582f1c9747e5649ace

Comment 1 Andrej Nemec 2018-09-20 10:33:00 EDT

Created python26 tracking bugs for this issue:

Affects: fedora-all [bug 1631421]

Comment 2 Miro Hrončok 2018-09-20 14:59:32 EDT

While python26 is not impacted, python2 actually is.

Here's a PR: https://src.fedoraproject.org/rpms/python2/pull-request/26

Comment 3 Andrej Nemec 2018-09-21 04:43:39 EDT

Created python2 tracking bugs for this issue:

Affects: fedora-all [bug 1631662]

Comment 4 Riccardo Schirone 2018-10-05 03:47:54 EDT

Hi Miro,

Why are you saying that python2 is affected on Fedora?
I'm asking because I wasn't able to reproduce this flaw on Linux and I believe it can be triggered on Windows only. Do you have more information on this?

Comment 5 Miro Hrončok 2018-10-09 09:00:57 EDT

Oh. I only meant that the code is in 2.7, I haven't checked that the flaw is actually usable or Python 2.7 on Linux vulnerable.

Comment 6 Riccardo Schirone 2018-10-10 03:33:46 EDT

This doesn't seem to be exploitable when os.name != 'nt' (Windows). The main problem is that quoting is done in distutils.py/spawn.py:_nt_quote_args and it just wraps arguments in `"`, without escaping previous existing `"`. Moreover, os.spawn in Windows uses CreateProcess underneath, which transforms the list of arguments in a single string, thus creating this flaw there. On linux, execv family functions are used and each argument is interpreted as a single filename, preventing this flaw.

Comment 8 Riccardo Schirone 2018-10-10 03:42:22 EDT

Statement:

This issue did not affect the versions of python as shipped with Red Hat Enterprise Linux 5, 6 and 7 as Linux does not use the vulnerable code.

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