Eavesdropping protection

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As Eavesdropping refers to technical measures and verification (so-called. "Sweep", s. U.) Of objects and spaces to the listening (listening) of conversations and data traffic to prevent.

A distinction is made between passive and active eavesdropping protection.

Passive eavesdropping protection

The passive eavesdropping protection deals with preventive measures such as B. with:

  • the planning and construction of tap-proof rooms, communication lines and vehicles
  • the prevention, suppression and corruption of electromagnetic waves ( compromising radiation e.g. from a monitor or a computer ) with e.g. B. Noise Generators
  • the establishment and configuration of secure communication with the help of e.g. B. cryptography , the use of encrypted UDP / TCP / IP connections ( VPN ) over which the information (including voice via VoIP ) is transported.

So come z. For example, special wallpapers with woven-in metal grids are sometimes used in rooms to be protected, which in principle function like a Faraday cage and thus achieve a certain electromagnetic shielding. This measure makes it extremely difficult to operate radio-based listening devices. However, it should be borne in mind that standard office wireless communication no longer works through such a shielded wall (e.g. via WLAN , Bluetooth , mobile phone , cordless phone , etc.).

Another possibility is to design eavesdropping-protected areas according to the zone model of the German Federal Office for Information Security (BSI) or to use low-emission devices, as described in the German IT basic protection catalog of the BSI.

Active eavesdropping protection ("Sweep")

Active eavesdropping protection means the targeted search (“sweep”) of eavesdropping devices (bugs - hence also called “bug search” in the vernacular) using technical equipment such as B .:

  • Broadband receiver / all- band receiver / frequency counter
  • Non-linear junction detectors (for finding semiconductors, i.e. electronic components )
  • Spectrum analyzer
  • Portable X-ray devices (e.g. for x-raying objects that cannot be dismantled, such as walls, telephone receivers, promotional gifts, etc.)
  • Thermoscopy ( thermal imaging camera ) to identify hidden power consumers through their heat radiation
  • Protocol analyzer
  • Line measuring devices
  • further measuring devices for visual and technical inspection

Mostly technical devices (e.g. telephone , copier , computer, etc.), furnishings (e.g. desks, armchairs, decorative objects such as sculptures, etc.) and building or vehicle structures (walls, double floors, false ceilings, etc.) are examined .)

Despite all the technology available today, sweeps are to a large extent a manual activity - wired or recording eavesdropping devices in particular can only be found through appropriate visual inspection. The following activities are part of the catalog of measures for a basic sweep:

  • Creation of a spectral analysis , comparison with a reference spectral analysis, checking of any deviations (new signals)
  • Detailed, technical and visual inspection of the spatial infrastructure such as walls, floors, power supply, cable ducts, pipe shafts and other objects in the room (computers, printers, furniture, etc.)
  • Review of the exterior facade

A sweep that has been carried out only ever represents a snapshot and therefore only an assessment of the situation at the time it was carried out. A. It makes sense to repeat the procedure at regular (or even irregular) intervals or if necessary (e.g. before and during important meetings).

Ideal state bug-proof

A communication link or a room is considered bug-proof if it cannot be bugged. However, this ideal state cannot be achieved in practice (theoretical exception: communication secured by quantum cryptography ). However, the risks can be greatly minimized by taking appropriate measures as part of passive eavesdropping protection. A meeting room that is virtually secure against eavesdropping should u. a. meet the following requirements:

  • No windows (to protect against laser microphone )
  • Complete solid construction
  • Protection against structure-borne noise
  • Walls, floor and ceiling are provided with a matching metal mesh ( Faraday cage )
  • No double floors or false ceilings
  • Tables and chairs made of (Plexi) glass without hidden cavities
  • No other furniture, pictures, stucco, decorative objects, etc. (i.e. absolutely unadorned room)
  • Room is permanently locked; every access must be logged and clearly assigned to a person
  • Sweep before each use of the room
  • Absolute ban on electronic devices (cell phones, laptops, etc.)

literature

  • Hans A. Wolfsperger: Electromagnetic shielding. Theory and practical examples, Springer Verlag, Berlin / Heidelberg 2008, ISBN 978-3-540-76912-5 .
  • Klaus-Rainer Müller: Corporate Security Handbook. 1st edition, Friedrich Vieweg & Sohn Verlag, Wiesbaden 2005, ISBN 978-3-322-96876-0 .

See also

Web links

Individual evidence

  1. ↑ IT-Grundschutz Catalogs: S 4.89 Radiation security Accessed on December 11, 2015.