Re: PFinger 0.7.8 format string vulnerability (#NISR16122002B)

[der Mouse <mouse@xxxxxxxxxxxxxxxxxxxxxx>]

>> *ON THE WIRE*, all 256 byte codes are legal, since [...]

> Yes noone said it is not, but fact is, the libc resolvers simply do
> not allow them, so you can send through the wire whatever you want it
> will not find its way to the fingerd.

This does not match my experience.

I control rDNS for my house network (my provider has installed CNAMEs
pointing into my domain for my address space); I tried picking a
currently-unused address and giving it a PTR record pointing to
"Host-%-sign.Rodents.Montreal.QC.CA".  I then told my nameserver to
reload the zone.

Using "host" on the address then printed the name I'd given,
Host-%-sign.Rodents.Montreal.QC.CA.  The resolver never even blinked.
(If you want to try your own resolver on it, I've left it up; the
address is 216.46.5.13.  I expect I'll be able to leave it up for at
least a month or so, but of course can't actually commit to that.)

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