linksys router + irc DoS

["Cade Cairns" <cairnsc () gmail com>]

Bug:

Certain Linksys (and possibly Netgear) routers will reset an IRC
connection when a malformed DCC request is received. In fact, it
doesn't even have to be a proper DCC request, the flaw can be
triggered simply by sending the following string such that it is
received by the user in some way.

DCC SEND "foo" 0 0 0

Presumably this is due to by the masquerading code that enables DCCs
to work correctly behind a NAT.

Workaround:

Connect to a non-standard port and the masquerading code won't
recognize it as an IRC connection.

Verified on:

    Linskys WRT54G

p.s. i am lazy and am not sending this to linksys. someone else can if
they feel inclined to do so. also i didn't find the problem; the
workaround was trivial.

--
Regards,
Cade Cairns