IRIX midikeys root exploit.

From: Larry W. Cashdollar (lwcashdat_private)
Date: Wed May 19 1999 - 08:25:59 PDT

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    Aleph1,
    	Please forgive me if this has already been on this list. I searched
    geek-girl with no luck.  I have been auditing our IRIX boxes and found what I
    believe to be a new vulnerability.
    	
    	On IRIX 6.5 systems (IRIX Release 6.5 IP28 )
    	# uname -a
    	IRIX64 devel 6.5 05190004
    	
    	The setuid root binary midikeys can be used to read any file on the
    system using its gui interface.  It can also be used to edit anyfile on the
    system.  I was able to get from guest account access to root access using the
    following procedure.
    	
    	
    	1) Choose an unpassworded account and telnet in. I like guest or lp.
    	
    	devel 25% id
    	uid=998 gid=998(guest)
    
    
    	2) Execute the midikeys application with display set to your host.
    
    	devel 26% ./midikeys
    	devel 27% Xlib:  extension "GLX" missing on display "grinch:0.0".
    	Xlib:  extension "GLX" missing on display "grinch:0.0".
    
    
    	3) under the midikeys window click sounds and then midi songs. This will 	
    	open a file manager type interface.
    	
    	4) You can enter the path and filename of files you which to read.
    	    including root owned with group/world read/write permissions unset.
    
    	5) If you select a file like "/usr/share/data/music/README" it will
    	appear in a text editor.  Use the text editor to open /etc/passwd and
    	make modifications at will. Save and enjoy.
    	
    So I removed the '*' from sysadm...
    
    $ su sysadm
    # id
    uid=0(root) gid=0(sys)
    
    devel 28%  ls -l /usr/sbin/midikeys
    -rwsr-xr-x    1 root     root      218712 Jan 10 17:19 /usr/sbin/midikeys
    
    	
    	I have tested this on 2 IRIX 6.5 hosts with success. A patch exists for
    	startmidi and stopmidi buffer overflows.
    	
    	More info on previous patch:
    	ftp://sgigate.sgi.com/security/19980301-01-PX).
    	
    	However, I didnt find any for midikeys.
    	
    	
    	-- Larry W. Cashdollar
    	   UNIX/Security Operations.
    	   Computer Sciences Corporation.
    	
    



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