## 7.14 Secure disposal or re-use of equipment

  

| **Control type** | **Information security properties** | **Cybersecurity concepts** | **Operational capabilities** | **Security domains** |

|------------------|------------------------------------|---------------------------|----------------------------------------|---------------------------|

| #Preventive | #Confidentiality | #Protect | #Physical_security #Asset_management | #Protection |

  

**Control**

  

Items of equipment containing storage media should be verified to ensure that any sensitive data and licensed software has been removed or securely overwritten prior to disposal or re-use.

  

**Purpose**

  

To prevent leakage of information from equipment to be disposed or re-used. **Guidance**

  

Equipment should be verified to ensure whether or not storage media is contained prior to disposal or re-use.

  

Storage media containing confidential or copyrighted information should be physically destroyed or the information should be destroyed, deleted or overwritten using techniques to make the original information non-retrievable rather than using the standard delete function. See 7.10for detailed guidance on secure disposal of storage media and 8.10for guidance on information deletion.

  

Labels and markings identifying the organization or indicating the classification, owner, system or network, should be removed prior to disposal, including reselling or donating to charity.

  

The organization should consider the removal of security controls such as access controls or surveillance equipment at the end of lease or when moving out of premises. This depends on factors such as:

  

a\) its lease agreement to return the facility to original condition;

  

b\) minimizing the risk of leaving systems with sensitive information on them for the next tenant (e.g. user access lists, video or image files);

  

c\) the ability to reuse the controls at the next facility.

  

**Other information**

  

Damaged equipment containing storage media can require a risk assessment to determine whether the items should be physically destroyed rather than sent for repair or discarded. Information can be compromised through careless disposal or re-use of equipment.

  

In addition to secure disk deletion, full-disk encryption reduces the risk of disclosure of confidential information when equipment is disposed of or redeployed, provided that:

  

a\) the encryption process is sufficiently strong and covers the entire disk (including slack space, swap files);

  

b\) the cryptographic keys are long enough to resist brute force attacks;

  

c\) the cryptographic keys are themselves kept confidential (e.g. never stored on the same disk). For further advice on cryptography, see 8.24.

  

Techniques for securely overwriting storage media differ according to the storage media technology and the classification level of the information on the storage media. Overwriting tools should be reviewed to make sure that they are applicable to the technology of the storage media.

  

See ISO/IEC 27040 for detail on methods for sanitizing storage media.