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This section of the ISM provides guidance on media usage.

Media management policy

Since media is capable of storing sensitive or classified information, it is important that a media management policy is developed and implemented to ensure that all types of media, and the information it stores, is protected in an appropriate manner. In many cases, an organisation’s media management policy will be closely tied to their removable media usage policy.

Security Control: 1549; Revision: 0; Updated: Aug-19; Applicability: O, P, S, TS
A media management policy is developed and implemented.

Removable media usage policy

Establishing a removable media usage policy can decrease the likelihood and consequence of accidental data spills and information loss or theft. In doing so, a removable media usage policy will likely cover the following:

  • permitted uses of removable media
  • permitted types of removable media
  • requirements for removable media registration
  • requirements for removable media labelling
  • requirements for the protection of removable media
  • requirements for the reporting of lost or stolen removable media
  • requirements for the sanitisation or destruction of removable media at the end of its life.

Security Control: 1359; Revision: 3; Updated: Aug-19; Applicability: O, P, S, TS
A removable media usage policy is developed and implemented.

Classifying media storing information

Media that is not correctly classified could be handled and stored inappropriately or accessed by personnel who do not have appropriate security clearances.

Security Control: 0323; Revision: 5; Updated: Feb-19; Applicability: O, P, S, TS
Media is classified to the highest sensitivity or classification of information stored on the media.

Classifying media connected to systems

There is no guarantee that information will not be copied to media while connected to a system unless read-only devices or read-only media are used.

Security Control: 0325; Revision: 5; Updated: Mar-19; Applicability: O, P, S, TS
Any media connected to a system is classified as the same sensitivity or classification as the system, unless the media is read-only, the media is inserted into a read-only device or the system has a mechanism through which read-only access can be ensured.

Reclassifying media

Media should always be protected according to the sensitivity or classification of the information it stores; however, if the sensitivity or classification of the information changes, so should the protection afforded to the media.

Security Control: 0331; Revision: 5; Updated: Sep-18; Applicability: O, P, S, TS
Media is reclassified if information copied onto the media is of a higher sensitivity or classification than the information already on the media, or information stored on the media is subject to a classification upgrade.

Security Control: 0330; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
If reclassifying media to a lower sensitivity or classification, the reclassification of all information on the media has been approved by the originator, or the media has been appropriately sanitised/destroyed and a formal administrative decision has been made to reclassify it.

Labelling media

Labelling media helps personnel to identify its sensitivity or classification and ensure that appropriate security controls are applied to its handling and usage.

While text-based protective markings are typically used for labelling media, there may be circumstances where colour-based protective markings or other marking schemes need to be used instead. In such cases, the marking scheme will need to be documented and personnel will need to be trained in its use.

Security Control: 0332; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
Media, with the exception of internally mounted fixed media within ICT equipment, is labelled with protective markings reflecting its sensitivity or classification.

Connecting media to systems

Some operating systems provide functionality to automatically execute programs that reside on media. While this functionality was designed with a legitimate purpose in mind (e.g. such as automatically loading a graphical user interface for a user to browse the contents of media or to install software residing on the media) it can also be used for malicious purposes. For example, an adversary can create a file on media that the operating system believes it should automatically execute. When the operating system executes the file, it can have the same effect as when a user explicitly executes malicious code; however, in this case the user is taken out of the equation as the operating system executes the file without explicitly asking for permission.

Device access control software allows greater control over media that can be connected to systems and how it can be used. This assists in preventing unauthorised media being connected to systems and, if desired, preventing information from being written to it. Media can also be prevented from connecting to systems by disabling connection ports in software or by physical means such as using wafer seals or applying epoxy. If physical means are used to prevent media connecting to systems, processes and procedures covering detection and reporting are needed in order to respond to attempts to bypass these security controls.

Security Control: 1600; Revision: 0; Updated: Aug-20; Applicability: O, P, S, TS
Media is sanitised before it is used with systems for the first time.

Security Control: 0337; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
Media is not used with systems that are not authorised to process, store or communicate the sensitivity or classification of information on it.

Security Control: 0341; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
Any automatic execution features for media are disabled in the operating system of systems.

Security Control: 0342; Revision: 5; Updated: Sep-18; Applicability: O, P, S, TS
Unauthorised media is prevented from connecting to systems via the use of device access control software, disabling connection ports, or by physical means.

Security Control: 0343; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
Media is prevented from being written to via the use of device access control software if there is no business requirement for its use.

Handling media

As media can be easily misplaced or stolen, mechanisms should be put in place to protect information stored on it. Furthermore, applying encryption to media may reduce the requirements for storage and physical transfer. Any reduction in requirements needs to be based on the original sensitivity or classification of information residing on the media and the level of assurance in the encryption software being used to encrypt the media.

Security Control: 0831; Revision: 5; Updated: Sep-18; Applicability: O, P, S, TS
Media is handled in a manner suitable for its sensitivity or classification.

Security Control: 1059; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
Media is encrypted with at least an Australian Signals Directorate Approved Cryptographic Algorithm.

Using media for data transfers

Organisations transferring data between systems belonging to different security domains are strongly encouraged to use write-once media. This will ensure that information from one of the systems cannot be accidently transferred onto the media then onto another system when the media is reused for the next transfer. Alternatively, if write-once media is not used, media should be sanitised between each data transfer.

Security Control: 0347; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
When transferring data manually between two systems belonging to different security domains, write-once media is used.

Security Control: 0947; Revision: 5; Updated: Aug-20; Applicability: O, P, S, TS
If not using write-once media for transferring data manually between two systems belonging to different security domains, the media is sanitised between each data transfer.

Further information

Further information on accounting for and storing media can be found in the ICT equipment and media section of the Guidelines for Physical Security.

Further information on labelling ICT equipment can be found in the ICT equipment usage section of the Guidelines for ICT Equipment.

Further information on reducing storage and physical transfer requirements can be found in the cryptographic fundamentals section of the Guidelines for Cryptography.

Further information on using media to transfer data between systems can be found in the Guidelines for Data Transfers.

Further information on the use of protective markings can be found in the Attorney-General’s Department (AGD)’s Protective Security Policy Framework (PSPF), Sensitive and classified information policy, at https://www.protectivesecurity.gov.au/information/sensitive-classified-information/Pages/default.aspx.

Further information on the storage and transfer of media can be found in AGD’s PSPF, Physical security for entity resources policy, at https://www.protectivesecurity.gov.au/physical/physical-security-entity-resources/Pages/default.aspx.