Robert Lemos, SecurityFocus
Phones, PCs and mobile devices that use the wireless Bluetooth
standard for short-range communications are open to eavesdropping
attacks if their users do not set long passwords, researchers said
The two-step attack can cause two devices to reestablish the link
between them, a process known as "pairing," and then use the data
exchanged during pairing to guess the password that secures the
connection in well under a second. A successful attack could allow an
attacker to eavesdrop and potentially issue commands to the other
device, said Avishai Wool, assistant professor of electrical
engineering at Tel Aviv University in Israel and a co-author of the
"At a minimum, it allows the attacker to eavesdrop on all the
subsequent encrypted communication between two Bluetooth devices,"
Wool said in an e-mail interview. "If the attacker can also fake his
own Bluetooth device address, he can potentially pretend to be one
device and pair with the other, which may allow him to issue
The attacker could conceivable mimic any other supported Bluetooth
device, such as a headset for a phone, he said. If the one device
could extract personal data from or issue commands to the other, then
so could the attacker.
The paper, which was presented at the MobiSys 2005 conference on
Monday, caused a stir among security experts because the technique is
the first general purpose attack to threaten Bluetooth devices. Past
attacks only worked against devices that improperly implemented
Bluetooth or under special circumstances.
The Bluetooth Special Interest Group (SIG), the organization that sets
the specifications for the standard, placed the latest attack in the
latter category, because devices that have longer, alphanumeric PINs
are effectively protected against the technique.