Re: Local Privilege Escalation via telnetd debug_open() and printsub()

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Collin Funk <[email protected]> writes:

> Justin Swartz <[email protected]> writes:
>
>> Greetings,
>>
>> I've identified two bugs in the debugging support provided by
>> telnetd that may be combined to achieve local privilege escalation
>> or arbitrary file corruption.

Thank you Justin!  Keep'em coming.

> The lack of sanitization is fine. It is only a problem when combined
> with the incorrect behavior of that link being followed.

I agree.

> I submitted a pull request to address that [1].
> [1] https://codeberg.org/inetutils/inetutils/pulls/20

I'm not completely opposed to solving it like this, but it feels like a
hack.

Why are we opening a hard-coded path file like this in the first place?
Couldn't we use syslog for logging here?  That's what ftpd --debug uses.

Did anyone review other telnetd implementations?  NetKit, BSD, Solaris,
etc.  Is --debug widely and consistently implemented?

/Simon

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