Re: Crashing an XTACACS authentication server

[alan () MANAWATU GEN NZ (Alan Brown)]

At 11:21 23/12/97 -0800, Coaxial Karma wrote:


> I recently discovered that when an ISP was using XTACACS server from
> Vikas Aggarwal (vikas () navya com) in a standalone mode, it was possible
> to
> make the XTACACS server crash by sending it different type of ICMP
> messages.

Nasty, but...

This reinforces the recommendation in Vikas' documentation that xtacacsd be
run out of inetd in persistent mode and not in standalone mode. Having
login/logout control die will at best generate a flurry of support calls
plus mess up time-based accounting or at worst, cost an ISP customers.

Thankfully Tacacs based clients usually default to "no response = no
access", so it only really becomes a security issue if a bogus tacacs
server can be installed on the network _and_ the tacacs servers are
configured to look at it. (Discounting forged udp tacacs responses).

AB