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Communications infrastructure
ASD ISMISM-1122

ASD ISM 1122 Secure TOP SECRET cable wall exits

What it says

Where wall penetrations exit a TOP SECRET area into a lower classified area, TOP SECRET cables are encased in conduit with all gaps between the TOP SECRET conduit and the wall filled with an appropriate sealing compound.

Quoted as published. Everything else on this page is written by Control Stack.

What it means

In plain English

Ensure TOP SECRET cables that pass through walls to lower security areas are protected by conduits and sealed.

If you have cables for sensitive or secret information running through walls into places that aren't as secure, it's vital to protect those cables. By putting the cables in a sturdy cover and sealing them properly, you ensure that no one can tamper with them or have unauthorised access, which helps to keep your sensitive information safe.

Why it matters

If TOP SECRET cables are not encased in conduit and wall gaps sealed, adversaries could intercept or tamper with signals as they exit to lower classified areas.

How to implement

  1. Facility Managers should work with a security contractor to assess wall penetrations where TOP SECRET cables pass through.

    They should identify any existing unprotected exits to ensure all cables are correctly encased. This can be done by physically inspecting the cable paths throughout the facility.

  2. Security contractors should install conduits to encase any exposed TOP SECRET cables.

    They should also ensure that every entry point of the conduit is sealed with a compound that meets security standards, to prevent tampering. This requires purchasing suitable sealing compounds and applying them at each identified location.

  3. IT security officers should regularly review the conduit system annually to ensure the integrity and security of the installations.

    This involves using a checklist to verify that all conduits are intact and seals are undamaged, and documenting any required repairs.

  4. Building maintenance teams should be trained on the importance of physical security for cabling and should perform routine checks for any unsealed or deteriorating sections of conduit.

    Training can include an explanation of what to look for during routine maintenance walks and who to notify for resolutions.

  5. System owners should document the locations of these conduits and seals in their security protocols, ensuring all staff are aware of these critical areas.

    This can be achieved by maintaining a detailed map or diagram in the office explaining where these lines are located and what to do if something looks suspicious.

Keep it running

Inspect TOP SECRET wall exit conduits and verify all annular gaps are fully filled with suitable sealing compound; repair cracks, shrinkage or loose fittings immediately.

Evidence and audit

  1. Check 1 of 5What an auditor asks for

    Ask for

    Building plans that show the location of all sand-witched conduits for TOP SECRET areas.

    Look at

    Whether each exit point into a lower classified area is documented.

    Good evidence

    Includes a clear, updated map with annotations of all conduits and seals.

  2. Check 2 of 5What an auditor asks for

    Look at

    The frequency of inspections and any noted issues.

    Good evidence

    Would show regularly logged inspections with detailed findings and resolution timelines.

  3. Check 3 of 5What an auditor asks for

    Ask for

    To see the inventory of sealing compounds used.

    Look at

    If the compounds meet security specification standards, such as those recommended by the Australian Cyber Security Centre (ACSC).

    Good evidence

    Should provide product details and compliance verification.

  4. Check 4 of 5What an auditor asks for

    Look at

    The content, frequency of the training, and attendance records.

    Good evidence

    Includes a course curriculum covering conduit security and a log of recent training attended by all relevant staff.

  5. Check 5 of 5What an auditor asks for

    Ask for

    Security protocols related to cable handling and protection.

    Look at

    The references to placing TOP SECRET cables in conduits.

    Good evidence

    Is a document that explicitly outlines procedures for cable protection, including contingency plans if a conduit is breached.

Mappings

Closest match in ISO/IEC 27001: A.7.12, Secure cabling for power and data, which this control partially meets.

ISO 27001

ISO/IEC 27001: 1 mapping

Mappings show how controls relate across frameworks. They do not imply full equivalence or certification.