[c-nsp] OSPF - Invalid length - Is this an attack?

[Sascha E. Pollok]

Nov 6 18:16:00 CET: %OSPF-4-BADLENGTH: Invalid length
  10246 in OSPF packet type 208 from 218.104.98.100
  (ID 37.68.117.149), GigabitEthernet15/0

IPs are far from our network ranges. Gig15/0 is
backbone facing.

Anyone with an idea what could be causing this?

Thanks
Sascha