Re: pcnfsd ...

[markz () REPSEC COM (Mark Zielinski)]

On Tue, 13 Oct 1998, ga wrote:

...

> I didn't succeed to use the ps630() hole explained in rep sec advisory
> (same as pr_cancel() phf-like bug). It's because pcnfsd_print.c checks
> if the file really exists (and then tries to rename it with the .spl
> extension). Therefore, if the file doesn't exist then an error is
> returned. However, if a local user creates a filename in the
> /var/spool/pcnfs directory which is in fact the command to execute (ex :
> /var/spool/pcnfs/FILENAME\nwhoami\nBLAH) then ps630() will work indeed,
> executing the command as root). I didn't tried it though.

...

FYI,

The way to remotely exploit the ps630 function is by tricking pcnfsd
into detecting a file, which will then allow you to get to the vulnerable
code.

You can do this by sending a '.', which will be there.

Mark Zielinski

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