Bug 1629975 (CVE-2018-16744)

Summary: CVE-2018-16744 mgetty: Command injection in faxrec.c
Product: [Other] Security Response Reporter: Pedro Sampaio <psampaio>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: abhgupta, dbaker, jokerman, msekleta, rschiron, sthangav, trankin, zdohnal
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: mgetty 1.2.1 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-10-25 22:17:41 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1629976, 1631238    
Bug Blocks: 1629987    
Attachments:
Description Flags
upstream patch none

Description Pedro Sampaio 2018-09-17 17:39:45 UTC 
An issue was discovered in mgetty before 1.2.1. In fax_notify_mail() in faxrec.c, the mail_to parameter is not sanitized. It could allow for command injection if untrusted input can reach it, because popen is used.

References:

https://www.x41-dsec.de/lab/advisories/x41-2018-007-mgetty
Comment 1 Pedro Sampaio 2018-09-17 17:40:16 UTC 
Created mgetty tracking bugs for this issue:

Affects: fedora-all [bug 1629976]
Comment 2 Riccardo Schirone 2018-09-20 09:19:30 UTC 
Only root can write to /etc/mgetty+sendfax/mgetty.config and set the `notify` option which `mail_to` is set to when the program runs.
Comment 5 Riccardo Schirone 2018-09-20 09:29:50 UTC 
Created attachment 1485085 [details]
upstream patch

This patch was extracted from mgetty-1.2.1
Comment 6 Riccardo Schirone 2018-09-20 09:32:42 UTC 
This flaw is very unlikely to be exploited since it requires the root account to set a wrong `notify` option.
Comment 8 Riccardo Schirone 2018-09-20 09:37:42 UTC 
Mitigation:

Make sure the `notify` option in /etc/mgetty+sendfax/mgetty.config does not contain characters that can be possibly interpreted by the shell and that the file is readable and writable only by root.
Comment 9 Fedora Update System 2019-02-27 01:15:28 UTC 
mgetty-1.1.37-10.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.
Comment 10 Fedora Update System 2019-02-27 03:28:18 UTC 
mgetty-1.1.37-11.fc29 has been pushed to the Fedora 29 stable repository. If problems still persist, please make note of it in this bug report.