Bug 1526142 – CVE-2017-17521 fontforge: Command injetion in help function uiutil.c

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Bug 1526142 - (CVE-2017-17521) CVE-2017-17521 fontforge: Command injetion in help function uiutil.c

Summary:	CVE-2017-17521 fontforge: Command injetion in help function uiutil.c

Status:	CLOSED WONTFIX

Aliases:	CVE-2017-17521

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:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20171214,repor...
Keywords:	Security

Depends On:	1526143
Blocks:	1526144
	Show dependency tree / graph

Reported:	2017-12-14 15:30 EST by Pedro Sampaio
Modified:	2018-01-13 23:46 EST (History)
CC List:	6 users (show)

See Also:
Fixed In Version:
Doc Type:	If docs needed, set a value
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2018-01-02 12:42:17 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
help function calls (5.21 KB, text/plain) 2018-01-02 12:38 EST, Pedro Yóssis Silva Barbosa	no flags	Details
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Pedro Sampaio 2017-12-14 15:30:54 EST

A flaw was found in FontForge through 20170731. uiutil.c does not validate strings before launching the program specified by the BROWSER environment variable, which might allow remote attackers to conduct argument-injection attacks via a crafted URL. A different vulnerability than CVE-2017-17534.

References:

https://security-tracker.debian.org/tracker/CVE-2017-17521

Comment 1 Pedro Sampaio 2017-12-14 15:31:23 EST

Created fontforge tracking bugs for this issue:

Affects: fedora-all [bug 1526143]

Comment 2 Pedro Yóssis Silva Barbosa 2018-01-02 12:38 EST

Created attachment 1375842 [details]
help function calls

Using a crafted URL, it is possible to inject command.

gbg> b *0x56f9bf

gdb> run --help

gbg> printf "%s", $rdi
"xdg-open" "http://fontforge.sf.net/overview.html" &

The thing is, though, the URL values seem to be all hardcoded and not possible to craft remotely (see attachment).

Comment 3 Pedro Yóssis Silva Barbosa 2018-01-02 12:42:27 EST

Statement:

This issue affects the versions of fontforge as shipped with Red Hat Enterprise Linux 6 and Red Hat Enterprise Linux 7. Red Hat Product Security has rated this issue as having Moderate security impact. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 4 Parag Nemade 2018-01-13 23:46:42 EST

Pedro,

Do you still want fedora bug open? I see this got closed as WONTFIX so fedora bug 1526143 should get closed as WONTFIX right?

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