Murray Associates | Security Report
Wireless Microphone Security
by Kevin D. Murray, CPP, CISM, CFE
The Short Story
even employees who are not invited to senior level
Never use analog FM wireless microphones.
meetings, for example.
Their transmissions are easily intercepted.
Watch this two minute movie.
http://youtu.be/T5Rq91zTyPg?hd=1
Eavesdropping on a specific meeting is only one
danger. Presenters often don’t know, or forget,
lavaliere microphones continue to
(See our resources list at the end for
broadcast when they are off stage. Only
secure alternatives.)
the receiver is turned off. This means
that side comments, hallway and
The Long Story
bathroom conversations will still be
Basically a miniature FM radio station,
intercepted. Even when they take the
a wireless microphone is worn by a
microphone off, they may not turn it off.
public speaker. The sound of the
When targeting off-site meetings, for
person’s voice is transmitted to a
example, the opposition will set up
nearby radio receiver, amplified and
radio receivers and recorders in one
played through loudspeakers so the
of the hotel’s rooms, or in an
audience can hear more easily. In
unoccupied car parked nearby. They
some cases it is also used to establish
a link to a video camera, or tape recorder.
Unfortunately, radio transmissions do not stop
at the receiver. Wireless microphones can
transmit for distances of 1000 feet to a mile.
are betting you will use wireless
microphones ...and make a variety of other
simple security mistakes. You will never see
them.
Any receiver tuned to the same frequency can
Murray Associates - Case History
listen in.
Our client, an international corporation, held
Wireless microphones are among the many
their annual sales meeting at a resort hotel and
gadgets which public speakers rely upon, along
with laser pointers, and large screen computer
displays. Wireless microphones allow the
presenter more freedom of movement.
Don’t Bug Yourself
conference center. A year’s worth of effort
involving new products, marketing strategies
and pricing was discussed that week. Very
confidential information.
Security was tight. Rooms were swept for
electronic eavesdropping devices. Access to
Commercial wireless microphones are designed
meeting rooms was controlled. Paperwork was
to broadcast crystal clear audio, and their signals
collected after each session. Participants were
travel much further than most people realize.
briefed on industrial espionage awareness.
Anyone can exploit this. Competitors, the press,
Their security manager had left nothing to chance.
©2014, Murray Associates | Electronic Surveillance Detection for Business & Government | counterespionage.com | 908-832-7900
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Murray Associates | Security Report
Wireless Microphone Security
by Kevin D. Murray, CPP, CISM, CFE
In the early morning hours before the opening
When securing meeting rooms, and during
of the meeting, our electronic countermeasures
meetings, monitor the radio frequency
team detected a strong radio transmission
spectrum for other emissions which could
emanating from the main conference room. It
carry room audio and/or video from the area.
permeated half the hotel room wing and out to
Avoid using a public address systems at off-
the parking lot. We calculated the signal could
be intercepted from a listening post in one of
thirty hotel rooms, or by using an automated
receiver/recorder hidden in the trunk of any of
the dozens of cars parked nearby.
We tracked the signal to a wireless stage
microphone, located inside an equipment case,
near the podium. The case belonged to the
audio-visual contractor.
site locations as that wiring can be tapped.
Use a self-contained podium system at low
volume instead. If you have no other choice,
use the venue’s direct wired microphone and
room speakers, at low volume.
If your organization owns analog FM wireless
microphones, replace them with a digital
encrypted system.
Was it mistakenly left on from the day before?
Secure Wireless Microphone Resources
No, we tested the battery voltage. It was fresh.
If a wireless microphone is absolutely
The audio/visual aids contractor had been
necessary, use one which employs digital
specifically told wireless microphones were not
transmission. The best systems also offer
wanted at the meeting. Why did he bring them?
encryption. This technology will dramatically
The contractor appeared nervous when asked
reduce eavesdropping opportunities.
about it.
• Audio-technica SpectraPulse
Intent could not be proved, and it doesn’t
Ultra WideBand - UWB
matter. Mistake or intentional, the meeting
Although UWB may also be encrypted, it is
would have been broadcast in either case.
generally accepted that this is not necessary
due to the inherent interception-resistance of
Wireless Microphone Security Checklist
Ban analog FM wireless microphones from
your meetings. Be explicit and be firm. Do
UWB transmissions1. http://tinyurl.com/SpectraPulse
• Beyerdynamic TG-1000 / MCW-D not allow this equipment in the room, even if
2.4 GHz, Direct Sequence Spread Spectrum
it will not be used. Guest speakers often
[DSSS] digital, encrypted.
bring their own equipment, so be sure to
http://tinyurl.com/no5tda4
advise them of your rule too.
1 http://www.audio-technica.com/cms/features/3abf313b29bb3c93/index.html)
©2014, Murray Associates | Electronic Surveillance Detection for Business & Government | counterespionage.com | 908-832-7900
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Murray Associates | Security Report
Wireless Microphone Security
by Kevin D. Murray, CPP, CISM, CFE
• Telex SAFE1000
remote control. Transmissions do not penetrate
NFSK digital, encryption.
opaque objects like radio waves. They can be
http://tinyurl.com/cpa885
intercepted optically, so limit use to rooms
• Revolabs
without windows.
DECT, 1.92 GHz
• http://tinyurl.com/b92o5h Globalav
Note: Although some iterations of DECT are
• http://tinyurl.com/y3sadh Tai Pong
hackable (https://dedected.org/trac) we believe
DECT provides adequate security for most
business situations. http://tinyurl.com/revolabs
• Lectrosonics Digital Hybrid Wireless™
This is a novel design which combines digitized
audio with an analog FM radio link. “Using a patented algorithm (US Patent
7,225,135) to encode 24-bit digital audio
• http://tinyurl.com/nmoposq Azden
FREE Resource...
Secure Wireless Microphone Systems (White Paper)
http://tinyurl.com/SecureWireless
#
s
#
information in the transmitter into an analog
—Kevin D. Murray CPP, CISM, CFE is a business
format, the encoded signal is then transmitted
counterespionage consultant and TSCM specialist
over an analog FM wireless link.”
with over three decades of experience.
http://tinyurl.com/pe6m4jz
Murray Associates is an independent security
• Sabine
consulting firm, providing eavesdropping
915 MHz / 2.4 GHz, “Smart Spectrum™” detection and counterespionage services to
This appears to be a combination of FM and
business, government and at-risk individuals.
spread spectrum technology. The manufacturer
From Boardrooms to private spaces, our
does not explain in their literature.
inspections reduce opportunities for
http://tinyurl.com/sfj37
competitive intelligence spying and help assure
• Shure ULX-D Digital Wireless System. personal privacy.
“All ULX-D components include AES-256
Headquartered in the New York metropolitan
encryption.”
area, a Murray Associates team can assist you
http://tinyurl.com/at5gbpf
quickly, anywhere in the United States, and
Infrared Wireless Microphones
internationally.
Visit http://counterespionge.com
An alternative to radio-frequency microphones
are infrared wireless microphones. Their
transmission mode is light, same as your TV
©2014, Murray Associates | Electronic Surveillance Detection for Business & Government | counterespionage.com | 908-832-7900
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