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Bug 235880

Summary: CVE-2007-1856 crontab denial of service
Product: Red Hat Enterprise Linux 5 Reporter: Josh Bressers <bressers>
Component: vixie-cronAssignee: Marcela Mašláňová <mmaslano>
Status: CLOSED ERRATA QA Contact: Brock Organ <borgan>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.0CC: k.georgiou, rbiba
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,source=vendorsec,reported=20070427,public=20070410
Fixed In Version: RHSA-2007-0345 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-05-17 14:26:06 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On:    
Bug Blocks: 224041    

Description Josh Bressers 2007-04-10 16:43:23 UTC
Raphael Marichez of Gentoo reported a denial of service flaw in vixie-cron.

By creating a hardlink to /etc/crontab, cron will stop executing the
/etc/crontab file and deposit an error message in /var/log/cron.

This can be easily tested by running:
ln /etc/crontab /tmp/crontab
tail -f /var/log/cron


Here is the patch from Open Wall Linux:
http://cvsweb.openwall.com/cgi/cvsweb.cgi/~checkout~/Owl/packages/vixie-cron/vixie-cron-4.1.20060426-owl-st_nlink.diff?rev=1.1;content-type=text%2Fplain

This flaw also affects RHEL 3 and 4.

Comment 5 RHEL Product and Program Management 2007-04-23 14:23:36 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Comment 6 Steve Grubb 2007-04-24 18:32:31 UTC
vixie-cron-4.1-68 was built to solve this issue.

Comment 19 Red Hat Bugzilla 2007-05-17 14:26:06 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2007-0345.html