Bug 716949 (CVE-2011-2500)

Summary: CVE-2011-2500 nfs-utils: Improper authentication of an incoming request when an IP based authentication used
Product: [Other] Security Response Reporter: Jan Lieskovsky <jlieskov>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: bfields, jlayton, mjc, steved
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-03-21 10:43:46 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: 715391, 716950    
Bug Blocks: 716955    

Description Jan Lieskovsky 2011-06-27 14:44:36 UTC
A security flaw was found in the way nfs-utils performed authentication
of an incoming request, when an IP based authentication mechanism was used
and certain file systems were exported to either to a netgroup or a wildcard
(e.g. *.my.domain), and some file systems (either the same or different to
the first set) were exported to specific hosts, IP addresses, or a subnet.
A remote attacker, able to create global DNS entries could use this flaw
to access above listed, exported file systems.

References:
[1] https://bugzilla.novell.com/show_bug.cgi?id=701702
[2] http://www.openwall.com/lists/oss-security/2011/06/27/7
    (CVE Request)

Relevant upstream patch:
[3] http://marc.info/?l=linux-nfs&m=130875695821953&w=2

Comment 1 Jan Lieskovsky 2011-06-27 14:46:17 UTC
Further details how to reproduce the issue (from [1]):
======================================================

1/ On a server, export a filesystem to an IP address and a random wildcard.
e.g.

/export 192.168.1.1(rw,no_root_squash,no_subtree_check)
*.mydomain.com(ro,no-subtree_check)

exportfs -av

2/ In /etc/hosts define some name to have two IP address; one that was given in
   /etc/exports, one that is the IP address of your attach client

  192.168.1.1 attacker
  192.168.0.1 attacker

3/ try to mount /export from 192.168.0.1

This should normally fail, but the bug causes it to succeed.

Comment 2 Jan Lieskovsky 2011-06-27 14:47:41 UTC
This issue did NOT affect the versions of the nfs-utils package, as shipped
with Red Hat Enterprise Linux 4 and 5.

--

This issue affects the versions of the nfs-utils package, as shipped with
Red Hat Enterprise Linux 6.

--

This issue affects the versions of the nfs-utils package, as shipped with
Fedora release of 14 and 15. Please schedule an update.

Comment 3 Jan Lieskovsky 2011-06-27 14:48:29 UTC
Created nfs-utils tracking bugs for this issue

Affects: fedora-all [bug 716950]

Comment 4 Jan Lieskovsky 2011-06-29 08:51:55 UTC
The CVE identifier of CVE-2011-2500 has been assigned to this issue:
http://www.openwall.com/lists/oss-security/2011/06/28/17

Comment 8 Huzaifa S. Sidhpurwala 2011-06-30 09:40:40 UTC
Statement:

This issue did not affect the versions of nfs-utils as shipped with Red Hat Enterprise Linux 4 and 5. The Red Hat Security Response Team has rated this issue as having low security impact; a future update in Red Hat Enterprise Linux 6 may address this flaw.

Comment 15 errata-xmlrpc 2011-12-06 18:53:53 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:1534 https://rhn.redhat.com/errata/RHSA-2011-1534.html