Bug 1490409 (CVE-2017-14482)

Summary: CVE-2017-14482 emacs: command injection flaw within "enriched mode" handling
Product: [Other] Security Response Reporter: Andrej Nemec <anemec>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: jonathan.underwood, jsynacek, msekleta, phracek, tim, yozone
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
A command injection flaw within the Emacs "enriched mode" handling has been discovered. By tricking an unsuspecting user into opening a specially crafted file using Emacs, a remote attacker could exploit this flaw to execute arbitrary commands with the privileges of the Emacs user.
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-09-22 08:41:54 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1490410, 1490451, 1490452    
Bug Blocks: 1490413    

Description Andrej Nemec 2017-09-11 13:40:27 UTC
Enriched mode implements an extension command to the text/enriched format called "x-display", which stores "display" text properties. It's possible to use this extension command to transparently execute arbitrary code in an Emacs process that opens a text/enriched file.

Upstream issue:

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=28350

Upstream patch:

https://git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-25&id=9ad0fcc54442a9a01d41be19880250783426db70

References:

http://seclists.org/oss-sec/2017/q3/422

Comment 1 Andrej Nemec 2017-09-11 13:40:58 UTC
Created emacs tracking bugs for this issue:

Affects: fedora-all [bug 1490410]

Comment 5 errata-xmlrpc 2017-09-19 18:36:49 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:2771 https://access.redhat.com/errata/RHSA-2017:2771

Comment 6 Stefan Cornelius 2017-09-25 13:16:35 UTC
Mitigation:

This issue can be mitigated by adding the following lines to the Emacs init file (for example ~/.emacs, ~/emacs.d/init.el, site-start.el) and avoiding options that would bypass normal initialization, like 'emacs -Q':

  ;; Mitigate CVE-2017-14482 in Emacs 25.2 and earlier
(require 'enriched)
(defun enriched-decode-display-prop (start end &optional param)
  (list start end))