Reader Yin wrote in after noticing a huge spike in unsolicited border gateway protocol (BGP) traffic. This same spike in BGP connections has also been noted on DShield's sensors [1].  Thankfully he provided a packet capture which contained numerous BGP OPEN [2] messages.

 Here is a snippet of the BGP packet with the relevant details:

These messages all originated from the same system, based in Korea.

The Korean system IP is part of: 

 AS Number          : AS9848

 AS Name            : SEJONGTELECOM-AS

From my understanding of BGP, this system is attempting to pass itself off as AS 65333, a private ASN [3] and poison the router with false details.

Whether misconfiguration or a malicious act is unknown at this point. Most, if not all routers should have basic protections in place to protect against this type of event having an effect [4].

Please let us know if you're seeing the same thing, can added anything further or if my analysis needs correcting.

UPDATE: Thank you to Reader Job for the clarification on private ASNs  

[1] https://isc.sans.edu/port.html?port=179

[2] http://www.inetdaemon.com/tutorials/internet/ip/routing/bgp/operation/messages/open.shtml

[3] http://www.apnic.net/services/services-apnic-provides/helpdesk/faqs/asn-faqs#UsePrivateASN

[4] http://www.inetdaemon.com/tutorials/internet/ip/routing/bgp/security/index.shtml

Chris Mohan --- Internet Storm Center Handler on Duty