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. udf should not be disabled on systems run on Microsoft Azure.
Solution
Run the following script to disable the udf filesystem: #!/usr/bin/env bash { l_mname='udf' # set module name if ! modprobe -n -v '$l_mname' | grep -P -- '^h*install /bin/(true|false)'; then echo -e ' - setting module: '$l_mname' to be not loadable' echo -e 'install $l_mname /bin/false' >> /etc/modprobe.d/'$l_mname'.conf fi if lsmod | grep '$l_mname' > /dev/null 2>&1; then echo -e ' - unloading module '$l_mname'' modprobe -r '$l_mname' fi if ! grep -Pq -- '^h*blacklisth+$l_mnameb' /etc/modprobe.d/*; then echo -e ' - deny listing '$l_mname'' echo -e 'blacklist $l_mname' >> /etc/modprobe.d/'$l_mname'.conf fi }