(Gentoo Issues Fix) fcron 'fcronsighup' Bugs Let Local Users View and Delete Files
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SecurityTracker Alert ID: 1012261 |
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SecurityTracker URL: http://securitytracker.com/id/1012261
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CVE Reference:
CAN-2004-1030, CAN-2004-1031, CAN-2004-1032, CAN-2004-1033
(Links to External Site)
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Date: Nov 19 2004
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Impact:
Disclosure of system information, Disclosure of user information, Modification of system information, Modification of user information
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Fix Available: Yes Vendor Confirmed: Yes
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Version(s): prior to 2.0.2
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Description:
iDEFENSE reported several vulnerabilities in fcron. A local user can view and delete arbitrary files on the target system. A local user can also supply an alternate configuration file.
It is reported that a local user can exploit the fcronsighup script to view arbitrary files with root privileges [CVE: CAN-2004-1030]. The local user can supply the file to be viewed as a parameter to fcronsighup, which will then attempt to parse the specified file as a configuration file. Lines that cannot be parsed will be displayed in an error message. A demonstration exploit command is provided:
fcronsighup /etc/shadow
It is also reported that a local user can direct the fcronsighup configuration file to a /proc entry owned by the 'root' user to supply arbitrary configuration settings to fcronsighup [CVE: CAN-2004-1031].
It is also reported that a local user can cause arbitrary files to be deleted [CVE CAN-2004-1032].
It is also reported that a local user can view the contents of the 'fcron.allow' and 'fcron.deny' files due to a file descriptor leak [CVE: CAN-2004-1033].
Karol Wiesek is credited with discovering these vulnerabilities.
The vendor was notified on October 21, 2004.
The original advisory is available at:
http://www.idefense.com/application/poi/display?id=157&type=vulnerabilities
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Impact:
A local user can view and delete arbitrary files on the target system.
A local user can supply an alternate configuration file.
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Solution:
Gentoo has released a fix and indicates that all Fcron users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-apps/fcron-2.0.2"
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Vendor URL: fcron.free.fr/ (Links to External Site)
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Cause:
Access control 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: Thu, 18 Nov 2004 16:44:22 -0500
Subject: [gentoo-announce] [ GLSA 200411-27 ] Fcron: Multiple vulnerabilities
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Gentoo Linux Security Advisory GLSA 200411-27
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http://security.gentoo.org/
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Severity: Normal
Title: Fcron: Multiple vulnerabilities
Date: November 18, 2004
Bugs: #71311
ID: 200411-27
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Synopsis
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Multiple vulnerabilities in Fcron can allow a local user to potentially
cause a Denial of Service.
Background
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Fcron is a command scheduler with extended capabilities over cron and
anacron.
Affected packages
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-------------------------------------------------------------------
Package / Vulnerable / Unaffected
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1 sys-apps/fcron <=3D 2.9.5 *>=3D 2.0.2
>=3D 2.9.5.1
Description
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Due to design errors in the fcronsighup program, Fcron may allow a
local user to bypass access restrictions (CAN-2004-1031), view the
contents of root owned files (CAN-2004-1030), remove arbitrary files or
create empty files (CAN-2004-1032), and send a SIGHUP to any process. A
vulnerability also exists in fcrontab which may allow local users to
view the contents of fcron.allow and fcron.deny (CAN-2004-1033).
Impact
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A local attacker could exploit these vulnerabilities to perform a
Denial of Service on the system running Fcron.
Workaround
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Make sure the fcronsighup and fcrontab binaries are only executable by
trusted users.
Resolution
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All Fcron users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=3Dsys-apps/fcron-2.0.2&qu=
ot;
References
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[ 1 ] CAN-2004-1030
http://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCAN-2004-1030
[ 2 ] CAN-2004-1031
http://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCAN-2004-1031
[ 3 ] CAN-2004-1032
http://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCAN-2004-1032
[ 4 ] CAN-2004-1033
http://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCAN-2004-1033
Availability
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This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
http://security.gentoo.org/glsa/glsa-200411-27.xml
Concerns?
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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
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Copyright 2004 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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