| Dmitry Teselkin | ee7b811 | 2018-08-22 12:46:08 +0300 | [diff] [blame] | 1 | # 1.1.1.6 Ensure mounting of squashfs filesystems is disabled |
| 2 | # |
| 3 | # Description |
| 4 | # =========== |
| 5 | # The squashfs filesystem type is a compressed read-only Linux filesystem |
| 6 | # embedded in small footprint systems (similar to cramfs). A squashfs image |
| 7 | # can be used without having to first decompress the image. |
| 8 | # |
| 9 | # Rationale |
| 10 | # ========= |
| 11 | # Removing support for unneeded filesystem types reduces the local attack |
| 12 | # surface of the server. If this filesystem type is not needed, disable it. |
| 13 | # |
| 14 | # Audit |
| 15 | # ===== |
| 16 | # Run the following commands and verify the output is as indicated: |
| 17 | # |
| 18 | # # modprobe -n -v squashfs |
| 19 | # install /bin/true |
| 20 | # # lsmod | grep squashfs |
| 21 | # <No output> |
| 22 | # |
| 23 | # Remediation |
| 24 | # =========== |
| 25 | # Edit or create the file /etc/modprobe.d/CIS.conf and add the following line: |
| 26 | # |
| 27 | # install squashfs /bin/true |
| 28 | # |
| 29 | # NOTE |
| 30 | # ==== |
| 31 | # In Ubuntu 16.04 squashfs is built into kernel, and 'install' command |
| 32 | # from modprobe.d dir has no effect. However, this is still checked by |
| 33 | # CIS-CAT in Ubuntu 16.04 benchmark v.1.0.0. This was removed in v.1.1.0. |
| 34 | # |
| 35 | parameters: |
| 36 | linux: |
| 37 | system: |
| 38 | kernel: |
| 39 | module: |
| 40 | squashfs: |
| 41 | install: |
| 42 | command: /bin/true |
| 43 | |