Full Disclosure mailing list archives

Re: [+] Vulnerability in less version 394 and prior


From: Jonathan Smith <smithj () freethemallocs com>
Date: Tue, 30 Oct 2007 21:04:27 -0800

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

glopeda.com wrote:
From: glopeda () glopeda com
Application: less 394 and prior
Type: Format strings vulnerability
Priority: Low

There exists a format strings bug in the less application present in
most flavors of UNIX.  It could be leveraged for privilege escalation
if the calling application is setuid/setgid and does not properly drop
privileges.

Meager demonstration:
$ export LESSOPEN=%s%n
$ less somefile
Segmentation fault
$

See http://www.glopeda.com for more details.


Still some strangeness on the latest version:
smithj@localhost ~ $  export LESSOPEN=%s%n
smithj@localhost ~ $  less route.txt
*** %n in writable segment detected ***
Aborted
smithj@localhost ~ $  conary query less
less=409-1-0.1[is: x86]

Given the details in the original post, I don't think this is a security
issue. If a program doesn't properly shed s{u,g}id bits, that program
should be fixed. This is still a bug, though, so I'm CCing the
maintainer on this email.

        smithj


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.7 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFHKAzbCG91qXPaRekRApAzAJ4mcIN5+vp9IjPWEQKRAP6q4dSl4QCfbkBh
7OPWx46AeHZF/9cGMqrBZHc=
=S7Fs
-----END PGP SIGNATURE-----

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/


Current thread: