Bug 550346 (CVE-2009-4411)

Summary:	CVE-2009-4411 acl: vulnerable to symlink attacks
Product:	[Other] Security Response	Reporter:	Vincent Danen <vdanen>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	kdudka, kreilly, qe-baseos-daemons, rcritten, steved, twoerner
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
URL:	http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2009-4411
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-08-22 15:47:45 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:	488674, 552665
Bug Blocks:

Description Vincent Danen 2009-12-24 16:20:25 UTC

Common Vulnerabilities and Exposures assigned an identifier CVE-2009-4411 to
the following vulnerability:

Name: CVE-2009-4411
URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-4411
Assigned: 20091223
Reference: MLIST:[oss-security] 20091223 CVE request: acl 2.2.47 always follows symlinks
Reference: URL: http://www.openwall.com/lists/oss-security/2009/12/23/2
Reference: CONFIRM: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=499076
Reference: CONFIRM: http://git.savannah.gnu.org/cgit/acl.git/commit/?id=63451a0
Reference: CONFIRM: http://oss.sgi.com/bugzilla/show_bug.cgi?id=790
Reference: BID:37455
Reference: URL: http://www.securityfocus.com/bid/37455
Reference: SECUNIA:37907
Reference: URL: http://secunia.com/advisories/37907
Reference: XF:acl-setfacl-getfacl-symlink(55004)
Reference: URL: http://xforce.iss.net/xforce/xfdb/55004

The (1) setfacl and (2) getfacl commands in XFS acl 2.2.47, when
running in recursive (-R) mode, follow symbolic links even when the
--physical (aka -P) or -L option is specified, which might allow local
users to modify the ACL for arbitrary files or directories via a
symlink attack.

Comment 22 Vincent Danen 2010-01-19 16:07:45 UTC

This issue does not affect Red Hat Enterprise Linux 3, 4 or 5 because the -P and -L options work as documented.

While investigating this issue, it was discovered that the setfacl -R option (whhen used without the -P or -L options) did behave contrary to what the manpage documentation specified by following symlinks in sub-directories when setting ACLs, in Red Hat Enterprise Linux 3 and 4.

Due to this behaviour, changing how -R behaves would cause a regression of long-established behaviour in setfacl.  The Red Hat Security Response Team have rated this issue as having low impact, and any potential fix has the risk of introducing a regression to relied upon (albeit incorrect) behaviour.

A separate bug was created to track this issue for Red Hat Enterprise Linux 4.  A fix may appear in future updates released as part of scheduled updates, if approved by product management (see bug #556880).