Bug 1260581 (CVE-2015-8777)

Summary:	CVE-2015-8777 glibc: LD_POINTER_GUARD in the environment is not sanitized
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	arjun.is, ashankar, codonell, dcallagh, fweimer, jakub, law, mfabian, mnewsome, pfrankli, sardella, slawomir
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	It was found that the dynamic loader did not sanitize the LD_POINTER_GUARD environment variable. An attacker could use this flaw to bypass the pointer guarding protection on set-user-ID or set-group-ID programs to execute arbitrary code with the permissions of the user running the application.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-10-21 10:29:23 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:	1260583, 1276761, 1383951
Bug Blocks:	1260582, 1415638

Description Adam Mariš 2015-09-07 10:13:32 UTC

A weakness in the dynamic loader has been found, making glibc of versions prior 2.22.90 affected. LD_POINTER_GUARD in the environment is not sanitizaed allowing attacker to easily bypass the pointer guarding protection on set-user-ID and set-group-ID programs.

Reproducing steps available at:

http://hmarco.org/bugs/glibc_ptr_mangle_weakness.html

CVE request:

http://seclists.org/oss-sec/2015/q3/504

Comment 1 Adam Mariš 2015-09-07 10:17:29 UTC

Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1260583]

Comment 2 Stefan Cornelius 2015-10-15 08:28:22 UTC

Upstream patch:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;h=a014cecd82b71b70a6a843e250e06b541ad524f7

Comment 3 Stefan Cornelius 2015-10-21 10:28:33 UTC

CVE has been requested, still no response:
http://www.openwall.com/lists/oss-security/2015/09/05/8

Comment 5 Fedora Update System 2016-02-17 12:49:42 UTC

glibc-2.21-11.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.

Comment 6 Dan Callaghan 2016-02-18 02:40:40 UTC

Seems like WONTFIX is not the correct resolution here?

Comment 8 Martin Prpič 2016-07-07 07:56:53 UTC

Mitigation:

The glibc pointer guard is a post-exploitation mitigation mechanism.  As such, it is only relevant if there are exploitable security vulnerabilities in the system.  Therefore, applying available security updates to the system is a possible mitigation for this issue.

In typical deployments, environment variables can only be set by users with shell access.  Restricting shell access to trusted users is another possible mitigation.

Comment 10 errata-xmlrpc 2017-08-01 18:12:37 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:1916 https://access.redhat.com/errata/RHSA-2017:1916