routing security

recent discussion reiterated that the ability to hijack address blocks is
a real threat. i am trying to understand in what other ways routing
security can be compromised in the current world. (while one can easily
come up with scores of potential dangers, it is hard to tell how realistic
a given danger is.)

i would appreciate (off-list) feedback on what you think the big problems
in routing security are. you can either provide your perspective on the
issue or rank the list below in order of importance.

a. router misconfig
b. address block hijacks (a special form of misconfig)
c. software bugs
d. compromised routers (how frequent is this?)
e. dos attacks targetted at routers
f. others (please specify)

bgp security gets a lot of attention. are people happy with
security of intra-domain routing?

  -- ratul