According to posts on the Bugtraq mailing list [ 1 / 2 ], Cisco’s popular router and switch operating system — IOS — suffers from two zero day Denial of Service (DoS) vulnerabilities. These advisories come from the penetration test team Of NCNIPC (China).
The advisories share minimal technical details about the two supposed flaws. They do say, attackers can trigger one DoS with a UDP packet flood and the other with SNMP packet sent to improper ports. In either case, the attack can put your IOS devices in a non-responsive state, requiring a reboot. By carrying out this sort of attach against your gateway router, and attacker can failry easily knock you offline
Cisco has since replied to these vulnerability allegations, saying they are researching the situations. However, they did not confirm or deny the DoS flaws, nor have they had time to release patches. Until they do, you can mitigate the risk of one of the flaws by disabling SNMP on your IOS device.
We’ll let you know more as soon as Cisco shares more complete details about these flaws. In the meantime, keep your eyes out for UDP floods. — Corey Nachreiner, CISSP