Title

The noexec option must be added to removable media partitions. (Cat III impact)

Discussion

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

Check Content

Identify any removable media that is configured on the system: # cat /etc/fstab /dev/mapper/vg_rhel6-lv_root / ext4 defaults 1 1 UUID=0be9b205-f8e6-4bf4-b0ba-1f235fc55936 /boot ext4 defaults 1 2 UUID=5D49-30B2 /boot/efi vfat umask=0077,shortname=winnt 0 0 /dev/mapper/vg_rhel6-lv_home /home ext4 defaults 1 2 /dev/mapper/vg_rhel6-lv_tmp /tmp ext4 defaults 1 2 /dev/mapper/vg_rhel6-lv_var /var ext4 defaults 1 2 /dev/mapper/vg_rhel6-lv_swap swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 /dev/sdc1 /media/usb vfat defaults,rw,noexec 0 0 If any of the identified removable media devices do not have "noexec" defined, this is a finding.

Fix Text

The "noexec" mount option prevents the direct execution of binaries on the mounted filesystem. Users should not be allowed to execute binaries that exist on partitions mounted from removable media (such as a USB key). The "noexec" option prevents code from being executed directly from the media itself, and may therefore provide a line of defense against certain types of worms or malicious code. Add the "noexec" option to the fourth column of "/etc/fstab" for the line which controls mounting of any removable media partitions.

Additional Identifiers

Rule ID: SV-218023r603264_rule

Vulnerability ID: V-218023

Group Title: SRG-OS-000480

Expert Comments

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