29 June 2007, 17:13

This number is not available: DoS vulnerabilities in Blackberry

Incorrect implementation of the SIP protocol results in three vulnerabilities in the Blackberry 7270 Wireless Handheld, which may affect VoIP or Voice over WLAN (VoWLAN) communications. If the Blackberry device receives malformed SIP INVITE messages, it becomes impossible to make or receive calls and the device fails to respond for about one minute. A reset is necessary to work around this problem. However, the affected user may not notice that an attack has taken place and may wait in vain for incoming calls via VoWLAN. According to the advisory, no other VoIP capabilities of the smartphone are affected by this attack.

Attackers may launch a successful denial-of-service attack by including several format string parameters in the FROM field of the SIP packet or by sending a URI without a host name. Such attacks can only be conducted from within an enterprise network, and the attacker must be able to connect to the company's PBX system. According to the vendor RIM and the service provider who has detected this vulnerability, Sipera, none of the three bugs can be exploited for malicious code injection.

RIM assert that the affected products use the BlackBerry Device Software 4.0 Service Pack 1 Bundle 83 (and prior versions) firmware, which is only used for the 7270 device. Other Blackberry devices are not affected by this problem. An update to BlackBerry Device Software 4.0 Service Pack 1 Bundle 108 or later versions will resolve these problems.

Only recently, the security of Blackberry became a public issue on another front, when the French newspaper Le Monde reported that French government officials were banned from using Blackberry devices for national security reasons, due to a threat of espionage by foreign intelligence services. However, the French government and senior economic intelligence advisor Alain Julliet later qualified that statement, saying that it referred not only to Blackberrys, but to all mobile devices.