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CIS Ubuntu 14.04 LTS - 1.1.1.6 Ensure mounting of udf filesystems is disabled

DevOps & Security
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Ensure the udf filesystem type is disabled to reduce attack surface

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-1-1-1-6/SKILL.md

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1.1.1.6 Ensure mounting of udf filesystems is disabled (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

The udf filesystem type is the universal disk format used to implement ISO/IEC 13346 and ECMA-167 specifications. This is an open vendor filesystem type for data storage on a broad range of media. This filesystem type is necessary to support writing DVDs and newer optical disc formats.

Rationale

Removing support for unneeded filesystem types reduces the local attack surface of the system. If this filesystem type is not needed, disable it.

Audit Procedure

modprobe -n -v udf
# Expected output: install /bin/true

lsmod | grep udf
# Expected output: <No output>

Expected Result

modprobe -n -v udf should return install /bin/true and lsmod | grep udf should return no output.

Remediation

# Edit or create the file /etc/modprobe.d/CIS.conf and add the following line:
echo "install udf /bin/true" >> /etc/modprobe.d/CIS.conf

# Unload the udf module:
rmmod udf

Default Value

By default, udf filesystem mounting is allowed.

References

  • CIS Ubuntu Linux 14.04 LTS Benchmark v2.1.0
  • CIS Controls: 13 Data Protection

Profile

  • Level 1