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This section of the ISM provides guidance on media destruction.

Media destruction process and procedures

Documenting a process and supporting procedures for media destruction will ensure that organisations carry out media destruction in an appropriate and consistent manner.

Security Control: 0363; Revision: 2; Updated: Aug-19; Applicability: O, P, S, TS
A media destruction process, and supporting media destruction procedures, is developed and implemented.

Media that cannot be sanitised

It is not possible to sanitise some types of media while maintaining a level of assurance that no information can be recovered.

Security Control: 0350; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
The following media types are destroyed prior to disposal as they cannot be sanitised:

  • microfiche and microfilm
  • optical discs
  • programmable read-only memory
  • read-only memory
  • other types of media that cannot be sanitised
  • faulty media that cannot be successfully sanitised.

Media destruction equipment

When physically destroying media, using approved equipment can provide a level of assurance that that information residing on the media is actually destroyed.

Approved equipment includes destruction equipment listed in the Security Construction and Equipment Committee (SCEC)’s Security Equipment Evaluated Products List, the Australian Security Intelligence Organisation (ASIO)’s Security Equipment Guide (SEG)-009, Optical Media Shredders, and ASIO’s SEG-018, Destructors. ASIO’s SEG-009 and SEG-018 are available from the Protective Security Policy GovTEAMS community or ASIO by email.

If using degaussers to destroy media, the United States’ National Security Agency maintains an Evaluated Products List for Magnetic Degaussers.

Security Control: 1361; Revision: 1; Updated: Sep-18; Applicability: O, P, S, TS
SCEC or ASIO approved equipment is used when destroying media.

Security Control: 1160; Revision: 2; Updated: Aug-20; Applicability: O, P, S, TS
If using degaussers to destroy media, degaussers evaluated by the United States’ National Security Agency are used.

Media destruction methods

The destruction methods given below are designed to ensure that recovery of information is impossible or impractical.

Security Control: 1517; Revision: 0; Updated: Sep-18; Applicability: O, P, S, TS
Equipment that is capable of reducing microform to a fine powder, with resultant particles not showing more than five consecutive characters per particle upon microscopic inspection, is used to destroy microfiche and microfilm.

Security Control: 0366; Revision: 2; Updated: Sep-18; Applicability: O, P, S, TS
One of the methods in the following table is used to destroy media.

Item

Destruction Methods

Furnace/
Incinerator

Hammer Mill

Disintegrator

Grinder/
Sander

Cutting

Degausser

Electrostatic memory devices

Yes

Yes

Yes

Yes

No

No

Magnetic floppy disks

Yes

Yes

Yes

No

Yes

Yes

Magnetic hard disks

Yes

Yes

Yes

Yes

No

Yes

Magnetic tapes

Yes

Yes

Yes

No

Yes

Yes

Optical disks

Yes

Yes

Yes

Yes

Yes

No

Semiconductor memory

Yes

Yes

Yes

No

No

No

Treatment of media waste particles

Following destruction, normal accounting and auditing procedures for media do not apply. However, depending on the destruction method used and the resulting particle size, it may still need to be stored and handled as classified waste.

Security Control: 0368; Revision: 6; Updated: Sep-18; Applicability: O, P, S, TS
The resulting waste for all destruction methods, except for furnace/incinerator and degausser, is stored and handled as per the following table.

Initial Media Handling

Screen Aperture Size Particles Can Pass Through

Less Than or Equal to
3 mm

Less Than or Equal to
6 mm

Less Than or Equal to
9 mm

TOP SECRET

OFFICIAL

SECRET

SECRET

SECRET

OFFICIAL

PROTECTED

SECRET

PROTECTED

OFFICIAL

OFFICIAL

OFFICIAL

OFFICIAL: Sensitive

OFFICIAL

OFFICIAL

OFFICIAL

OFFICIAL

OFFICIAL

OFFICIAL

OFFICIAL

Degaussing magnetic media

Degaussing magnetic media changes the alignment of magnetic domains resulting in information being permanently corrupted.

Coercivity (the resistance of magnetic material to change) varies between magnetic media types and between brands and models of the same type of media. Care is needed when degaussing magnetic media since a degausser of insufficient strength will not be effective. The United States’ National Security Agency provides information on the common types of magnetic media and their associated coercivity ratings with their list of evaluated degaussers.

Since 2006, perpendicular magnetic media has been available. As some degaussers are only capable of sanitising longitudinal magnetic media, care needs to be taken to ensure that a suitable degausser is used.

Finally, to ensure that degaussers are being used in the correct manner to achieve an effective destruction outcome, product-specific directions provided by degausser manufacturers should be followed.

Security Control: 0361; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
A degausser of sufficient field strength for the coercivity of the magnetic media is used, with the field strength being checked at regular intervals.

Security Control: 0838; Revision: 2; Updated: Sep-18; Applicability: O, P, S, TS
A degausser capable of the magnetic orientation (longitudinal or perpendicular) of the magnetic media is used.

Security Control: 0362; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
Any product-specific directions provided by degausser manufacturers are followed.

Supervision of destruction

To verify that media is appropriately destroyed, the process needs to be supervised by at least one person cleared to the sensitivity or classification of the media being destroyed.

Security Control: 0370; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
The destruction of media is performed under the supervision of at least one person cleared to the sensitivity or classification of the media being destroyed.

Security Control: 0371; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
Personnel supervising the destruction of media supervise the handling of the media to the point of destruction and ensure that the destruction is completed successfully.

Supervision of accountable material destruction

Accountable material is more important than standard media. As such, its destruction should be supervised by at least two personnel who sign a destruction certificate afterwards.

Security Control: 0372; Revision: 4; Updated: Sep-18; Applicability: O, P, S, TS
The destruction of accountable material is performed under the supervision of at least two personnel cleared to the sensitivity or classification of the media being destroyed.

Security Control: 0373; Revision: 3; Updated: Sep-18; Applicability: O, P, S, TS
Personnel supervising the destruction of accountable media supervise the handling of the material to the point of destruction, ensure that the destruction is completed successfully and sign a destruction certificate afterwards.

Outsourcing media destruction

ASIO has approved National Association for Information Destruction AAA certified destruction services with endorsements, as specified in ASIO’s Protective Security Circular (PSC)-167, External destruction of security classified information, for the outsourced destruction of media. ASIO’s PSC-167 is available from the Protective Security Policy GovTEAMS community or ASIO by email.

Security Control: 0840; Revision: 3; Updated: Sep-18; Applicability: O, P, S
When outsourcing the destruction of media to an external destruction service, a National Association for Information Destruction AAA certified destruction service with endorsements, as specified in ASIO’s PSC-167, is used.

Security Control: 0839; Revision: 2; Updated: Sep-18; Applicability: O, P, S, TS
The destruction of TOP SECRET media or accountable material is not outsourced.

Further information

Further information on the destruction of ICT equipment can be found in the ICT equipment sanitisation and disposal section of the Guidelines for ICT Equipment.

The United States’ National Security Agency’s Evaluated Products List for Magnetic Degaussers is available at https://www.nsa.gov/resources/everyone/media-destruction/.

Further information on the SCEC’s Security Equipment Evaluated Products List is available at https://www.scec.gov.au/catalogue.