Skype denies DoS attack

As Skype`s outage continues, speculation about its causes is gearing up, but it has denied it has fallen victim to a denial of service attack, reports IT News.

In a posting on its Web site, Skype blamed the issues on a "deficiency in an algorithm within Skype networking software. This controls the interaction between the user`s own Skype client and the rest of the Skype network."

A later update informed users that the problems will likely continue throughout the day on Friday. Users started reporting problems with the free Internet calling service on Thursday morning.

New exploits against VOIP continue to emerge, but experts say these demonstrations reveal the need for vigilant security and are not fatal flaws to the technology, says Computerworld.

At Black Hat this month, researchers released hacking tools against VOIP, signalling protocols H.323 and AIX as well as tools to insert audio into VOIP calls.

At Defcon, a tool that automatically probes the Session Initiation Protocol for vulnerabilities was released to enable the covert piggy-backing of data over VOIP streams.

VOIP vendors say they deliver scalability and security, says Computerworld. InteropLabs testing mostly proved them right in multivendor settings.

However, testing also revealed some implementation 'gotchas` in both of those areas, and pinpointed a few missing pieces when it comes to key exchange for securing VOIP traffic.

This testing showed that 802.11a networks deliver higher call quality than 802.11b or 802.11g networks. While 802.11a is far less subject to interference than the 802.11b/g/n frequencies, the biggest difference in call quality turned out to be rate synchronisation.