[SECURITY] [DLA 1723-1] cron security update

Package : cron
Version : 3.0pl1-127+deb8u2
CVE ID : CVE-2017-9525 CVE-2019-9704 CVE-2019-9705 CVE-2019-9706
Debian Bug : 809167

Various security problems have been discovered in Debian's CRON scheduler.

CVE-2017-9525

Fix group crontab to root escalation via the Debian package's
postinst script as described by Alexander Peslyak (Solar Designer) in
http://www.openwall.com/lists/oss-security/2017/06/08/3

CVE-2019-9704

DoS: Fix unchecked return of calloc(). Florian Weimer discovered that
a missing check for the return value of calloc() could crash the
daemon, which could be triggered by a very large crontab created by a
user.

CVE-2019-9705

Enforce maximum crontab line count of 1000 to prevent a malicious
user from creating an excessivly large crontab. The daemon will log a
warning for existing files, and crontab(1) will refuse to create new
ones.

CVE-2019-9706

A user reported a use-after-free condition in the cron daemon,
leading to a possible Denial-of-Service scenario by crashing the
daemon. 

For Debian 8 "Jessie", these problems have been fixed in version
3.0pl1-127+deb8u2.

We recommend that you upgrade your cron packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS

–

mike gabriel aka sunweaver (Debian Developer)
fon: +49 (1520) 1976 148

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mail: [email protected], http://sunweavers.net