# Disable udf Kernel Module to Harden Linux Kernel Security

- Source: https://support.icompaas.com/support/solutions/articles/62000234912-disable-udf-kernel-module-to-harden-linux-kernel-security
- 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 2

**Description:**  
The udf kernel module provides support for the Universal Disk Format (UDF) filesystem, commonly used on optical media such as DVDs and Blu-ray discs.

**Rationale:** Disabling the udf kernel module when not required reduces the kernel attack surface by preventing the loading of unnecessary filesystem modules, minimizing potential vulnerabilities.

**Impact:** Pros:

-   Reduces kernel attack surface by disabling unused filesystem support.  
    
-   Helps mitigate risks related to UDF filesystem vulnerabilities.  
    

Cons:

-   Systems needing to mount UDF filesystems will be unable to do so if the module is disabled.  
    

**Default Value:** The udf kernel module may be available and enabled by default on many Linux systems.

**Pre-requisites:**

-   Root or sudo privileges to modify kernel module configurations.  
    
-   Access to /etc/modprobe.d/ to configure blacklisting or disabling.
    

**Remediation:**

### **Test Plan:**

**Using Linux command line:**

1.  Check if the udf module is loaded:  
    
     lsmod | grep udf
    
2.  Verify blacklist or disable entries:  
    
    grep -r udf /etc/modprobe.d/
    
3.  Test module load behavior:  
    
     modprobe -n -v udf
    
    Expected output should show the module is disabled, e.g., install /bin/false.  
    

### **Implementation Plan:**

**Using Linux command line:**

1.  Create or edit /etc/modprobe.d/udf.conf:  
    
    echo "install udf /bin/false" > /etc/modprobe.d/udf.conf
     echo "blacklist udf" >> /etc/modprobe.d/udf.conf
    
2.  Unload the module if currently loaded:  
    
     modprobe -r udf
    
3.  Reboot the system or reload kernel module configurations.  
    

### **Backout Plan:**

**Using Linux command line:**

1.  Remove blacklist and disable entries:  
    
    sed -i '/udf/d' /etc/modprobe.d/udf.conf
    
      
    
2.  Optionally reload the module:  
    
    modprobe udf
    
3.  Reboot the system.  
    

**References:**

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