cis-ubuntu1204-v110-4-1

name	cis-ubuntu1204-v110-4-1
description	Restrict Core Dumps
category	cis-os-hardening
version	1.1.0
author	cyberstrike-official
tags	["cis","ubuntu",12.04,"linux","process-hardening","core-dumps","security-limits","sysctl"]
cis_id	4.1
cis_benchmark	CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

4.1 Restrict Core Dumps (Scored)

Profile Applicability

• Level 1

Description

A core dump is the memory of an executable program. It is generally used to determine why a program aborted. It can also be used to glean confidential information from a core file. The system provides the ability to set a soft limit for core dumps, but this can be overridden by the user.

Rationale

Setting a hard limit on core dumps prevents users from overriding the soft variable. If core dumps are required, consider setting limits for user groups (see limits.conf(5)). In addition, setting the fs.suid_dumpable variable to 0 will prevent setuid programs from dumping core. The apport service if active will override the fs.suid_dumpable variable setting and automatically create core dump reports. The whoopsie service monitors apport core dump reports and transmits them to Canonical.

Audit Procedure

Using Command Line

Perform the following to determine if core dumps are restricted:

grep "hard core" /etc/security/limits.conf
sysctl fs.suid_dumpable

Ensure no start conditions are listed for the apport or whoopsie services:

initctl show-config apport apport
initctl show-config whoopsie whoopsie

Expected Result

The first command should return: * hard core 0 The second command should return: fs.suid_dumpable = 0 The apport and whoopsie services should have no start conditions or be disabled.

Remediation

Using Command Line

Add the following line to the /etc/security/limits.conf file:

* hard core 0

Add the following line to the /etc/sysctl.conf file:

fs.suid_dumpable = 0

Uninstall the apport and whoopsie packages or comment out any start lines in /etc/init/apport.conf and /etc/init/whoopsie.conf files:

#start on runlevel [2345]

Default Value

By default, core dumps are enabled and apport may be active on Ubuntu 12.04.

References

• CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0