Vixie Cron crontab Privilege Lowering Failure Vulnerability

BID:2687

Info

Vixie Cron crontab Privilege Lowering Failure Vulnerability

Bugtraq ID: 2687
Class: Serialization Error
CVE:
Remote: No
Local: Yes
Published: May 07 2001 12:00AM
Updated: May 07 2001 12:00AM
Credit: Initially posted to Bugtraq in a Debian Security Advisory (DSA-054-1) on May 7, 2001. Reportedly discovered by Sebastian Krahmer <[email protected]>.
Vulnerable: Paul Vixie Vixie Cron 3.0.1
+ SuSE Linux 7.1 x86
 + SuSE Linux 7.1 sparc
 + SuSE Linux 7.1 ppc
 + SuSE Linux 7.1
Paul Vixie Vixie Cron 3.0 pl1
+ Debian Linux 2.2 sparc
 + Debian Linux 2.2 powerpc
 + Debian Linux 2.2 arm
 + Debian Linux 2.2 alpha
 + Debian Linux 2.2 68k
 + Debian Linux 2.2
+ Progeny Debian 1.0
Not Vulnerable: SuSE Linux 7.1 alpha
Redhat Linux 7.1
Redhat Linux 7.0
Redhat Linux 6.1
Redhat Linux 6.2
Paul Vixie Vixie Cron 3.0 pl1-67
+ Debian Linux 2.2 sparc
 + Debian Linux 2.2 powerpc
 + Debian Linux 2.2 arm
 + Debian Linux 2.2 alpha
 + Debian Linux 2.2 68k
 + Debian Linux 2.2

Discussion

Vixie Cron crontab Privilege Lowering Failure Vulnerability

Vixie cron is an implementation of the popular UNIX program that runs user-specified programs at periodic scheduled times.

When a parsing error occurs after a modification operation, crontab will fail to drop privileges correctly for subsequent modification operations.

This vulnerability may be exploited to gain root privileges locally.

Exploit / POC

Vixie Cron crontab Privilege Lowering Failure Vulnerability

During SIA analysis of this vulnerability, Cade Cairns <[email protected]> wrote proof-of-concept exploit code.

Another exploit written by Michael Zalewski <[email protected]> and Sebastian Krahmer <[email protected]> has also been submitted.

Solution / Fix

Vixie Cron crontab Privilege Lowering Failure Vulnerability

Solution:
Conectiva has released an advisory CLA-2003:757 as an update to the original advisory CLSA-2003:628 that was released to address this issue. Further details relating to the application of fixes is available in the referenced advisory. Fix is linked below.

Several vendors have released fixed upgrades:


Paul Vixie Vixie Cron 3.0 pl1

Paul Vixie Vixie Cron 3.0.1

References

Vixie Cron crontab Privilege Lowering Failure Vulnerability

References:

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