# Ensure nosuid Mount Option is Set on /var Partition to Prevent Privilege Escalation

- Source: https://support.icompaas.com/support/solutions/articles/62000234975-ensure-nosuid-mount-option-is-set-on-var-partition-to-prevent-privilege-escalation
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [CIS Amazon Linux 2 Benchmark v3.0.0](https://support.icompaas.com/support/solutions/62000112696) › [CIS Amazon Linux 2 Benchmarks](https://support.icompaas.com/support/solutions/folders/62000169265)
- Last updated: 2026-05-29
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

**Profile Applicability:** • Level 1

**Description:**  
 The nosuid mount option prevents the operation of set-user-identifier (setuid) and set-group-identifier (setgid) bits on executable files in the mounted filesystem. Applying this option to /var helps mitigate privilege escalation risks by disallowing setuid and setgid programs from running there.

**Rationale:** Setting the nosuid option on /var reduces the risk that malicious or unauthorized binaries within /var could be exploited for privilege escalation.

**Impact:** Pros:

-   Helps prevent privilege escalation attacks via setuid/setgid binaries in /var.  
    
-   Improves overall system security.  
    

Cons:

-   May affect applications relying on setuid/setgid binaries in /var (rare).
    

**Default Value:** The nosuid option is typically not set on /var unless explicitly configured.

**Pre-requisites:**

-   Root or sudo privileges to modify /etc/fstab and remount filesystems.
    
-   /var must be mounted as a separate partition.
    

**Remediation:**

### **Test Plan:**

**Using Linux command line:**

1.  Check current mount options for /var:  
    
     mount | grep /var
    
2.  Verify if nosuid is included in /etc/fstab for /var:  
    
     grep /var /etc/fstab
    
    Expected output: Mount options for /var include nosuid.
    

### **Implementation Plan:**

**Using Linux command line:**

1.  Edit /etc/fstab to add nosuid to /var mount options. For example:  
    
    /dev/<partition>  /var  ext4  defaults,nodev,nosuid,noexec  0  0
    
      
    
2.  Remount /var with new options:  
    
     mount -o remount,nosuid /var
    
3.  Verify mount options:  
    
     mount | grep /var
    

###   
**Backout Plan:**

**Using Linux command line:**

1.  Remove nosuid from /var mount options in /etc/fstab.  
    
2.  Remount /var without nosuid:  
    
     mount -o remount /var
    
3.  Verify mount options:  
    
     mount | grep /var
    

---

**References:**

-   CIS Amazon Linux 2 Benchmark v3.0.0  
    
-   [NIST SP 800-53 Revision 5 - SC-7  
    ](https://csrc.nist.gov/publications/detail/sp/800-53/rev-5/final#sc-7)

## Related compliance guidance

- [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them.
- [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.