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New types of denial of service attacks threatened the security of mobile data networks, a senior telecoms security researcher warned last week.

Krishan Sabnani, vice president of networking research at Bell Labs, said inherent weaknesses in the mobile IP protocol allow the launch of attacks that are relatively straightforward to mount but hard to detect and thwart.

The attacks would take the form of repeatedly setting up and releasing connections, for example, a form of attack analogous with the SYN Flood assaults that have long being a problem on the fixed-line (wired) internet. Other attacks might rely on preventing mobile devices from going into a dormant mode, thereby draining battery life.

"We need to especially monitor the mobile networks – with limited bandwidth and terminal battery — for DOS attacks," Sabnani said during a session at the Cyber Infrastructure Protection Conference at City College of New York last Thursday, Network World reports.

Worse still the resources needed to launch an attack might be out of all proportion to the damage that could be inflicted, Sabnani suggested.

"One cable modem user with 500Kbps upload capacity can attack over one million mobile users simultaneously," he said.

Sabnani outlined various types of attack against mobile IP networks: re-establishing connections after they have been released to create congestion at radio network controllers, thereby causing problems for legitimate subscribers; sending packets to prevent a mobile device from going into sleep mode; placing rogue devices on a network that generate spurious traffic that can be hard to pin down; and excessive port scanning as a result of connected devices that are infected with computer malware.

Bell Labs' is using Sabnani's research into DOS threats to develop security appliances designed especially for mobile network architecture and protocols, marketed by Alcatel-Lucent as the 9900 Wireless Network Guardian.

"We have developed algorithms based on traffic profiling and statistical models that can detect low-volume wireless DOS attacks," Sabnani explained. "The system detects and mitigates traffic that will cause RNC signaling overload, unnecessary airlink usage, paging overload, and unnecessary subscriber battery drain." ®

http://www.theregister.co.uk/2009/06...le_dos_threat/