1.1.1.4 Ensure mounting of udf filesystems is disabled - blacklist

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Information

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.

Impact:

Microsoft Azure requires the usage of udf. Thus do not disable udf if this system is to run on MS Azure.

Solution

Edit or create a file in the /etc/modprobe.d/ directory ending in .conf with a line that reads install udf /bin/false.
Example:

# echo 'install udf /bin/false' >> /etc/modprobe.d/udf.conf
# echo 'blacklist udf' >> /etc/modprobe.d/udf.conf

Run the following command to unload the udf module:

# modprobe -r udf

See Also

https://workbench.cisecurity.org/files/3549