| name | cis-ubuntu1804-v220-1-1-4-1 |
| description | Ensure separate partition exists for /var/tmp |
| category | cis-storage |
| version | 2.2.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-18.04","partition","var-tmp","mount"] |
| cis_id | 1.1.4.1 |
| cis_benchmark | CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
Ensure separate partition exists for /var/tmp
Profile
Level 2 - Server / Level 2 - Workstation, Assessment: Automated
Description
The /var/tmp directory is a world-writable directory used for temporary storage by all users and some applications.
Rationale
Since the /var/tmp directory is intended to be world-writable, there is a risk of resource exhaustion if it is not bound to a separate partition. In addition, making /var/tmp its own file system allows an administrator to set additional mount options such as the noexec option on the mount, making /var/tmp useless for an attacker to install executable code.
Impact
Resizing filesystems is a common activity in cloud-hosted servers. Separate filesystem partitions may prevent tying the overall disk management to one large volume. It may be necessary to use Logical Volume Management (LVM) or similar tools to create a flexible partitioning scheme for /var/tmp.
Audit Procedure
Command Line
Run the following command and verify the output shows that /var/tmp is mounted:
Expected Result
/var/tmp /dev/sda3 ext4 rw,nosuid,nodev,noexec,relatime
Remediation
Command Line
For specific configuration requirements of the /var/tmp mount for your environment, modify /etc/fstab:
Creating a new partition is a destructive operation that typically requires a reinstallation or use of LVM.
Default Value
By default /var/tmp is not a separate partition.
References
- http://tldp.org/HOWTO/LVM-HOWTO/
- NIST SP 800-53 Rev. 5: CM-6
CIS Controls
v8 - 3.3 Configure Data Access Control Lists (IG 1, IG 2, IG 3)
v7 - 14.6 Protect Information through Access Control Lists (IG 1, IG 2, IG 3)
MITRE ATT&CK Mappings: T1499, T1499.001 (TA0005) - M1022