Bug 1612659 (CVE-2018-10928)

Summary:	CVE-2018-10928 glusterfs: Improper resolution of symlinks allows for privilege escalation
Product:	[Other] Security Response	Reporter:	Sam Fowler <sfowler>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	abhgupta, anoopcs, atumball, bmcclain, dbaker, dblechte, dfediuck, eedri, humble.devassy, jokerman, jonathansteffan, kkeithle, matthias, mgoldboi, michal.skrivanek, ndevos, public, ramkrsna, rhs-bugs, sankarshan, sbonazzo, security-response-team, sfowler, sherold, sisharma, ssaha, sthangav, trankin, vbellur
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	glusterfs-3.12.14, glusterfs-4.1.4	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in RPC request using gfs3_symlink_req in glusterfs server which allows symlink destinations to point to file paths outside of the gluster volume. An authenticated attacker could use this flaw to create arbitrary symlinks pointing anywhere on the server and execute arbitrary code on glusterfs server nodes.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-10 10:35:17 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:	1613683, 1616829, 1625068, 1625071
Bug Blocks:	1609600

Description Sam Fowler 2018-08-06 05:52:44 UTC

The Gluster filesystem allows for symlink destinations to point to filepaths outside of the mounted volume. An attacker could exploit this via a crafted request to create arbitrary files and subsequently execute arbitrary privileged commands.

Comment 1 Sam Fowler 2018-08-06 05:52:54 UTC

Acknowledgments:

Name: Michael Hanselmann (hansmi.ch)

Comment 5 Doran Moppert 2018-08-16 01:54:53 UTC

Statement:

This issue did not affect Red Hat Enterprise Linux 6 and 7 as the flaw is present in glusterfs-server, which is not shipped there.

This flaw affects glusterfs versions included in Red Hat Virtualization 4 Hypervisor. However, in recommended configurations, the vulnerability is only exposed to hypervisor administrators and can not be exploited from virtual machines or other hosts on the network. For Red Hat Virtualization, Product Security has rated this flaw as Moderate. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 7 Siddharth Sharma 2018-09-04 05:39:13 UTC

Created glusterfs tracking bugs for this issue:

Affects: fedora-all [bug 1625068]

Comment 9 errata-xmlrpc 2018-09-04 06:25:09 UTC

This issue has been addressed in the following products:

  Red Hat Gluster Storage 3.4 for RHEL 7
  Native Client for RHEL 7 for Red Hat Storage

Via RHSA-2018:2607 https://access.redhat.com/errata/RHSA-2018:2607

Comment 10 errata-xmlrpc 2018-09-04 06:26:33 UTC

This issue has been addressed in the following products:

  Red Hat Gluster Storage 3.4 for RHEL 6
  Native Client for RHEL 6 for Red Hat Storage

Via RHSA-2018:2608 https://access.redhat.com/errata/RHSA-2018:2608

Comment 11 Siddharth Sharma 2018-09-04 14:58:00 UTC

Mitigation:

To limit exposure of gluster server nodes :  

1. gluster server should be on LAN and not reachable from public networks.  
2. Use gluster auth.allow and auth.reject.  
3. Use TLS certificates to authenticate gluster clients.

caveat: This does not protect from attacks by authenticated gluster clients.

Comment 12 Siddharth Sharma 2018-09-05 07:46:13 UTC

upstream fix:

https://review.gluster.org/21068

Comment 13 errata-xmlrpc 2018-11-05 14:57:27 UTC

This issue has been addressed in the following products:

  Red Hat Virtualization 4 for Red Hat Enterprise Linux 7

Via RHSA-2018:3470 https://access.redhat.com/errata/RHSA-2018:3470