|
Thursday, June 09, 2005
Security flaw exposes mobile phones to taps
The old first-generation mobile phones could be easily monitored by anyone with a “scanning all-band receiver” because the system used an analog transmission system, like an ordinary radio transmitter.
Second-generation digital phones, on the other hand, are harder to monitor because they use a digitally compressed transmission.
However, the state can tap mobile phones with the cooperation of the phone company. It’s also possible for organizations with the correct technical equipment, such as large corporations, to monitor mobile phone communications and decrypt the audio.
A special device called an International Mobile Equipment Identification (IMSI) catcher pretends to the mobile phones in its vicinity to be a legitimate base station of the mobile phone network.
This is possible because while the mobile phone has to authenticate itself to the mobile telephone network, the network does not authenticate itself to the mobile phone.
This blatant flaw in GSM security was intentionally introduced to facilitate eavesdropping without the knowledge or cooperation of the mobile phone network.
Once the mobile phone has accepted the IMSI catcher as its base station, the IMSI catcher can deactivate GSM encryption using a special flag.
All calls made from the tapped mobile phone go through the IMSI-catcher and are then passed on to the mobile network.
Up to now, no phone is known that actively alerts the user when a base station or an IMSI-catcher deactivates GSM encryption. Some phones include a special monitor mode (activated with secret codes or special software) that displays GSM operating parameters such as encryption while a call is being made.
But no matter whether GSM encryption is active or not, users should not trust the encryption to be secure enough that an eavesdropper cannot decrypt the encrypted data. ((From Wikipedia)
(June 9, 2005 issue)
Write letter to the editor.Click here.
Join the Sun.Star message board.Click here. |
|
[return to top]
[home]
[network page]
|
LOCAL NEWS
BUSINESS
OPINION
SPORTS
LIFESTYLE
FEATURE
SUPERBALITA
WEEKEND
|
