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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