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Security Advisory Low: vixie-cron security, bug fix, and enhancement update

Advisory: RHSA-2012:0304-3
Type: Security Advisory
Severity: Low
Issued on: 2012-02-21
Last updated on: 2012-02-21
Affected Products: Red Hat Enterprise Linux (v. 5 server)
Red Hat Enterprise Linux Desktop (v. 5 client)
CVEs (cve.mitre.org): CVE-2010-0424

Details

An updated vixie-cron package that fixes one security issue, several bugs,
and adds one enhancement is now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having low
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

The vixie-cron package contains the Vixie version of cron. Cron is a
standard UNIX daemon that runs specified programs at scheduled times. The
vixie-cron package adds improved security and more powerful configuration
options to the standard version of cron.

A race condition was found in the way the crontab program performed file
time stamp updates on a temporary file created when editing a user crontab
file. A local attacker could use this flaw to change the modification time
of arbitrary system files via a symbolic link attack. (CVE-2010-0424)

Red Hat would like to thank Dan Rosenberg for reporting this issue.

This update also fixes the following bugs:

* Cron jobs of users with home directories mounted on a Lightweight
Directory Access Protocol (LDAP) server or Network File System (NFS) were
often refused because jobs were marked as orphaned (typically due to a
temporary NSS lookup failure, when NIS and LDAP servers were unreachable).
With this update, a database of orphans is created, and cron jobs are
performed as expected. (BZ#455664)

* Previously, cron did not log any errors if a cron job file located in the
/etc/cron.d/ directory contained invalid entries. An upstream patch has
been applied to address this problem and invalid entries in the cron job
files now produce warning messages. (BZ#460070)

* Previously, the "@reboot" crontab macro incorrectly ran jobs when the
crond daemon was restarted. If the user used the macro on multiple
machines, all entries with the "@reboot" option were executed every time
the crond daemon was restarted. With this update, jobs are executed only
when the machine is rebooted. (BZ#476972)

* The crontab utility is now compiled as a position-independent executable
(PIE), which enhances the security of the system. (BZ#480930)

* When the parent crond daemon was stopped, but a child crond daemon was
running (executing a program), the "service crond status" command
incorrectly reported that crond was running. The source code has been
modified, and the "service crond status" command now correctly reports that
crond is stopped. (BZ#529632)

* According to the pam(8) manual page, the cron daemon, crond, supports
access control with PAM (Pluggable Authentication Module). However, the PAM
configuration file for crond did not export environment variables correctly
and, consequently, setting PAM variables via cron did not work. This update
includes a corrected /etc/pam.d/crond file that exports environment
variables correctly. Setting pam variables via cron now works as documented
in the pam(8) manual page. (BZ#541189)

* Previously, the mcstransd daemon modified labels for the crond daemon.
When the crond daemon attempted to use the modified label and mcstransd was
not running, crond used an incorrect label. Consequently, Security-Enhanced
Linux (SELinux) denials filled up the cron log, no jobs were executed, and
crond had to be restarted. With this update, both mcstransd and crond use
raw SELinux labels, which prevents the problem. (BZ#625016)

* Previously, the crontab(1) and cron(8) manual pages contained multiple
typographical errors. This update fixes those errors. (BZ#699620,
BZ#699621)

In addition, this update adds the following enhancement:

* Previously, the crontab utility did not use the Pluggable Authentication
Module (PAM) for verification of users. As a consequence, a user could
access crontab even if access had been restricted (usually by being denied
in the access.conf file). With this update, crontab returns an error
message that the user is not allowed to access crontab because of PAM
configuration. (BZ#249512)

All vixie-cron users should upgrade to this updated package, which resolves
these issues and adds this enhancement.


Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Updated packages

Red Hat Enterprise Linux (v. 5 server)

SRPMS:
vixie-cron-4.1-81.el5.src.rpm     MD5: 6a090c8b6fcabf8061a2a85a138e1bbb
SHA-256: 1314bcbd79c68788bb1ca405d47c4a44fb6889c0a0749b4f451b383016e78c73
 
IA-32:
vixie-cron-4.1-81.el5.i386.rpm     MD5: 3578441fed08846cc4b099bfbd181784
SHA-256: 0069d760e8ba0b1c9439baeddb769c23d32992505efcefe81c4d688233483619
vixie-cron-debuginfo-4.1-81.el5.i386.rpm     MD5: 1dd4a842f2b984af9fbc23054d6fa37d
SHA-256: e5a6def92436576f661c2f13d579374f5ca20e01dcc51396af24f7ed60a8a078
 
IA-64:
vixie-cron-4.1-81.el5.ia64.rpm     MD5: 385aa59c8913e2e74cd97cf63140d2e2
SHA-256: 730fa12207e619c753fb47a326e15d7dc34dce7b1734c1e3d317d0b42ad56e59
vixie-cron-debuginfo-4.1-81.el5.ia64.rpm     MD5: fe25fa5e0812f9ba068638498f09875c
SHA-256: 879e331f7be520c265aed8c37721670435c175ba30943d3874d25661078a158a
 
PPC:
vixie-cron-4.1-81.el5.ppc.rpm     MD5: be40b35616253bbb18e7fc667b04a191
SHA-256: b0df05b3e9621aae7562ff47b2912d5fc1d475df8a919a7189d5c70594465d63
vixie-cron-debuginfo-4.1-81.el5.ppc.rpm     MD5: 665b8d14f12bc8af5dbddfd541d30197
SHA-256: 1f4ecb9dd79acd59d69feb719d2c06b7a400048f4069ec56b1391dee89f0ebec
 
s390x:
vixie-cron-4.1-81.el5.s390x.rpm     MD5: 616f659256ded7b3fee91324e27dc4bd
SHA-256: 6e54e5fa4f5a59e8a847245452117fdfa1a639c6b01f54cc2e67509d6f1e3710
vixie-cron-debuginfo-4.1-81.el5.s390x.rpm     MD5: 14c0b06a4fcbc55acb56d8c4f9233e7f
SHA-256: 57ff90f49eb34858a9c2b3f8f26b2c76ea34f252f4f567362ea723e84205c6d7
 
x86_64:
vixie-cron-4.1-81.el5.x86_64.rpm     MD5: 883f4d566b9c0dc96322e20129d290f7
SHA-256: 680c91f262dc98a4a5533f6d5b7a1b611a2efa06667106f4dbf7cedc0e5195e3
vixie-cron-debuginfo-4.1-81.el5.x86_64.rpm     MD5: bff184ee94553ad26349fcf9f175c6c2
SHA-256: 1f931ccf283cc289e0b30cee4dfc8c5c53d5a04df9de9a019cdfaa1c23119f06
 
Red Hat Enterprise Linux Desktop (v. 5 client)

SRPMS:
vixie-cron-4.1-81.el5.src.rpm     MD5: 6a090c8b6fcabf8061a2a85a138e1bbb
SHA-256: 1314bcbd79c68788bb1ca405d47c4a44fb6889c0a0749b4f451b383016e78c73
 
IA-32:
vixie-cron-4.1-81.el5.i386.rpm     MD5: 3578441fed08846cc4b099bfbd181784
SHA-256: 0069d760e8ba0b1c9439baeddb769c23d32992505efcefe81c4d688233483619
vixie-cron-debuginfo-4.1-81.el5.i386.rpm     MD5: 1dd4a842f2b984af9fbc23054d6fa37d
SHA-256: e5a6def92436576f661c2f13d579374f5ca20e01dcc51396af24f7ed60a8a078
 
x86_64:
vixie-cron-4.1-81.el5.x86_64.rpm     MD5: 883f4d566b9c0dc96322e20129d290f7
SHA-256: 680c91f262dc98a4a5533f6d5b7a1b611a2efa06667106f4dbf7cedc0e5195e3
vixie-cron-debuginfo-4.1-81.el5.x86_64.rpm     MD5: bff184ee94553ad26349fcf9f175c6c2
SHA-256: 1f931ccf283cc289e0b30cee4dfc8c5c53d5a04df9de9a019cdfaa1c23119f06
 
(The unlinked packages above are only available from the Red Hat Network)

Bugs fixed (see bugzilla for more information)

455664 - Adoptions at the crontab orphanage needed
460070 - cronjobs in /etc/cron.d entries with an invalid username produce no error in the logs
476972 - crontab error with @reboot entry
480930 - Make crontab a PIE
529632 - [PATCH] "service crond status" return invalid status
541189 - cron and /etc/security/pam_env.conf problem
565809 - CVE-2010-0424 vixie-cron, cronie: Race condition by setting timestamp of user's crontab file, when editing the file
625016 - crond requires a restart if mcstransd is stopped
699620 - Typo in patch for crond manpage removes mention of cron.d
699621 - man page typo -- two be -- should be not two be's ;)


References


Keywords

orphan,, pam,, pie


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https://www.redhat.com/security/team/key/#package

The Red Hat security contact is secalert@redhat.com. More contact details at http://www.redhat.com/security/team/contact/