RSI.0007.05-26-98.SUN.LIBAUTH


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                   Repent Security Incorporated, RSI
                       [ http://www.repsec.com ]


           *** RSI ALERT ADVISORY ***
 

--- [CREDIT] --------------------------------------------------------------

Matt Conover: Discovered vulnerability
Mark Zielinski: Author of advisory


--- [SUMMARY] -------------------------------------------------------------

Announced:     Aug 4, 1998
Report code:   RSI.0007.05-26-98.SUN.LIBAUTH
Report title:  Sun Microsystem's library libauth
Vulnerability: Insufficient bounds checking
Vendor status: Vendor has been contacted on May 26, 1998
Patch status:  No patch currently available
Platforms:     Solaris 2.2, 2.3, 2.4, 2.5, 2.5.1, 2.6
Vulnerable:    Several libary functions in libauth have buffer overflows
Reference:     http://www.repsec.com/advisories.html
Impact:         If exploited, an attacker could potentially compromise
               local root access on your server


--- [DETAILS] -------------------------------------------------------------

Problem:       Two buffer overflows exist in Sun Microsystem's libauth
         library.

         When ia_open_session () is called, it copies both the
         connecting hostname and username into seperate local 
         buffers with no bounds checking.  ia_open_session ()
               attempts to write the information passed to it into these
               buffers to maintain utmpx information on the user logging
               into the system.  Because these buffers are set at a fixed
               value of 257 bytes, it is possible to cause a buffer
               overflow.

               While overwriting the buffer, the attacker can manipulate
               the stack and execute their own commands, possibly gaining
               root access on the system.

         Functions we have found vulnerable:
         ---------------------------------------------------

         ia_open_session ()      : Copies information passed to it
                                         into two local buffers which can
                 result in a buffer overflow.

               Potentially vulnerable programs
         ----------------------------------------------------

           1. login
           2. in.ftpd
                 3. in.uucpd
                 4. rpc.rexd

         These vulnerabilities are present in Sun Microsystems 
               Solaris 2.2, 2.3, 2.4 2.5, 2.5.1 and 2.6. 

         For more information on this type of attack, point your
         web browsers to http://www.repsec.com/bofs.html.


--- [FIX] -----------------------------------------------------------------

Solution:      No fixes are currently available.


--- [PATCH] ---------------------------------------------------------------

Solution:      Wait for Sun Microsystem's to release an official patch.


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Repent Security Incorporated (RSI)
13610 N. Scottsdale Rd.
Suite #10-326
Scottsdale, AZ 85254

E-mail: advise@repsec.com
WWW: http://www.repsec.com
FTP: ftp://ftp.repsec.com

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Copyright August 1998  RepSec, Inc.

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