cis-ubuntu1604-v200-1-5-4

DevOps & Security

Ensure core dumps are restricted

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_16.04_LTS_Benchmark_v2.0.0/cis-ubuntu1604-v200-1-5-4/SKILL.md

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CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - 1.5.4

Profile Applicability

Level 1 - Server
Level 1 - Workstation

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.

Audit Procedure

Command Line

Run the following commands and verify output matches:

grep -Es '^(\*|\s).*hard.*core.*(\s+#.*)?#x27; /etc/security/limits.conf /etc/security/limits.d/*

Expected output: * hard core 0

sysctl fs.suid_dumpable

Expected output: fs.suid_dumpable = 0

grep "fs.suid_dumpable" /etc/sysctl.conf /etc/sysctl.d/*

Expected output: fs.suid_dumpable = 0

Run the following command to check if systemd-coredump is installed:

systemctl is-enabled coredump.service

If enabled, masked, or disabled is returned systemd-coredump is installed.

Expected Result

Hard core limit should be set to 0, fs.suid_dumpable should be 0, and if systemd-coredump is installed it should be configured properly.

Remediation

Command Line

Add the following line to /etc/security/limits.conf or a /etc/security/limits.d/* file:

* hard core 0

Set the following parameter in /etc/sysctl.conf or a /etc/sysctl.d/* file:

fs.suid_dumpable = 0

Run the following command to set the active kernel parameter:

sysctl -w fs.suid_dumpable=0

IF systemd-coredump is installed, edit /etc/systemd/coredump.conf and add/modify the following lines:

Storage=none
ProcessSizeMax=0

Run the command:

systemctl daemon-reload

Default Value

Not applicable.

References

None.

CIS Controls

Controls Version	Control
v7	5.1 Establish Secure Configurations

Assessment Status

Automated