SV: PIX Privilege Escalation Vulnerability

["Jan Nielsen" <jan () boyakasha dk>]

Does not seem to work on ASA 8.0(2)

Regards
Jan

-----Oprindelig meddelelse-----
Fra: listbounce () securityfocus com [mailto:listbounce () securityfocus com] På
vegne af tbbunn () ctc net
Sendt: 24. januar 2008 04:42
Til: vuln-dev () securityfocus com
Emne: PIX Privilege Escalation Vulnerability

Back in May of last year I started doing research on any possible security
flaws that exist in the Pix/ASA Finesse operating System, versions 7.1 and
7.2. I discovered that a design flaw that was previously unknown in Finesse
will allow a level 0 user to escalate their privilege to level 15. I believe
the vulnerability may originate in the local authentication service, thus
not being possible to exploit when Radius and TACACS is implemented.
Implementing AAA in any other way that keeps the passwords locally defined
seems to have no affect on the vulnerability. I have been able to repeatedly
bypass the privilege-exec login both locally, through the console and
remotely, through a telnet connection. After many attempts I have found that
the SSH service does not seem to suffer from the vulnerability. 
        I am now going to go over the simplicity of the exploit and I will
be releasing a white paper hopefully sooner than later on the specifics of
the underlying cause. Once a user has logged on to the user-exec (level0) of
the device they will then be able to proceed with the <enable> command which
should give you a login prompt. At this prompt if you move your cursor
forward with a space or character(it doesn't matter if there are more then
one), and then proceed to delete any spaces or characters, by holding down
the backspace a second after deleting the last character it should
immediately drop you into level 15 privilege-exec mode. This attack was
originally performed on a PIX 515E running version 7.2 of Finesse. I will be
posting all updates regarding this exploit as they come, and I apologize for
it taking so long to release this information.

Terry B Bunn
LunarTEkINT Labs 


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