(Gentoo Issues Fix) ncpfs Access Control Bug Lets Local Users Access Files and Buffer Overflow May Let Local Users Execute Arbitrary Code
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SecurityTracker Alert ID: 1013051 |
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SecurityTracker URL: http://securitytracker.com/id/1013051
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CVE Reference:
CAN-2005-0013, CAN-2005-0014
(Links to External Site)
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Date: Jan 31 2005
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Impact:
Disclosure of system information, Disclosure of user information, Execution of arbitrary code via local system, Root access via local system
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Fix Available: Yes Vendor Confirmed: Yes
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Version(s): prior to 2.2.6
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Description:
Two vulnerabilities were reported in ncpfs. A local user can access arbitrary files with elevated privileges. A local user may also be able to execute arbitrary code with elevated privileges.
The ncp_fopen_nwc() function in 'ncpfs-2.2.0.18/lib/ncplib.c' does not properly control access to files. The function does not check to make sure that the file ownership matches the uid of the calling user. As a result, a local user can invoke ncpmount to cause ncpfs to access a file that the user would otherwise not be permitted to access [CVE: CAN-2005-0013].
The opt_set_volume_after_parsing_all_options() function in 'ncpfs-2.2.5/sutil/ncplogin.c' does not properly validate the length of user-supplied command line parameters. A local user can supply a specially crafted path value to trigger a buffer overflow, potentially allowing the local user to execute arbitrary code with elevated privileges [CVE: CAN-2005-0014].
Erik Sjolund is credited with discovering these flaws.
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Impact:
A local user can access arbitrary files with elevated privileges.
A local user may also be able to execute arbitrary code with elevated privileges.
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Solution:
Gentoo has released a fix and indicates that all ncpfs users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-fs/ncpfs-2.2.6"
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Cause:
Access control error, Boundary error
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Underlying OS:
Linux (Gentoo)
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Message History:
This archive entry is a follow-up to the message listed below.
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Source Message Contents
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Date: Sun, 30 Jan 2005 19:55:45 +0100
Subject: [gentoo-announce] [ GLSA 200501-44 ] ncpfs: Multiple vulnerabilities
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Gentoo Linux Security Advisory GLSA 200501-44
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http://security.gentoo.org/
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Severity: Normal
Title: ncpfs: Multiple vulnerabilities
Date: January 30, 2005
Bugs: #77414
ID: 200501-44
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Synopsis
========
The ncpfs utilities contain multiple flaws, potentially resulting in
the remote execution of arbitrary code or local file access with
elevated privileges.
Background
==========
ncpfs is a NCP protocol network filesystem driver that allows access to
NetWare services, to mount volumes of NetWare servers or print to
NetWare print queues.
Affected packages
=================
-------------------------------------------------------------------
Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 net-fs/ncpfs < 2.2.6 >= 2.2.6
Description
===========
Erik Sjolund discovered two vulnerabilities in the programs bundled
with ncpfs: there is a potentially exploitable buffer overflow in
ncplogin (CAN-2005-0014), and due to a flaw in nwclient.c, utilities
using the NetWare client functions insecurely access files with
elevated privileges (CAN-2005-0013).
Impact
======
The buffer overflow might allow a malicious remote NetWare server to
execute arbitrary code on the NetWare client. Furthermore, a local
attacker may be able to create links and access files with elevated
privileges using SUID ncpfs utilities.
Workaround
==========
There is no known workaround at this time.
Resolution
==========
All ncpfs users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-fs/ncpfs-2.2.6"
References
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[ 1 ] CAN-2005-0013
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0013
[ 2 ] CAN-2005-0014
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0014
[ 3 ] ncpfs ChangeLog
ftp://platan.vc.cvut.cz/pub/linux/ncpfs/Changes-2.2.6
Availability
============
This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
http://security.gentoo.org/glsa/glsa-200501-44.xml
Concerns?
=========
Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.
License
=======
Copyright 2005 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).
The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.
http://creativecommons.org/licenses/by-sa/2.0
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