PDAs used as weapons against WLANs
PDAs used as weapons against WLANs
The Australian Computer Emergency Response Team has discovered that handheld devices can be used to launch attacks on wireless local are networks by anonymous infiltrators.
The attackers can use a low-powered PDA and a widely available wireless networking card to cause havoc to all WLAN traffic within range.
The most common wireless networking protocol, the IEEE 802.11, is extremely vulnerable because of its medium access control function. Specialised hardware used to be required to saturate the wireless frequency with high-power radiation, which is not available to subtle attackers.
But now, however, these low cost devices are able to allow semi-skilled hackers to defer transmission of data for the duration of the attack. When under threat, the device behaves as if the channel is always busy, preventing the transmission of any data over the wireless network.
Due to the recent popularity of handheld devices, AUSCERT has issued a warning that companies should be aware of these attacks increasing over time, and they should move to wireless technologies that are not vulnerable to jamming.
Independent vendors have admitted that there is currently no defence against this type of attack for DSSS based WLANs.
The success of an attack can also be improved by an increase in the transmission power of the attacking device, and the use of a high-grain antennae.
Vulnerable devices include any that support the 802.11, 802.11b and low-speed 802.11g wireless standards. Devices that use 802.11a or high-speed 802.11g, above 20mbps, are not vulnerable, according to AUSCERT.
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