RSI.0005.05-14-98.SUN.LIBNSL



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


           *** RSI ALERT ADVISORY ***


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

Matt Conover: Discovered the vulnerabilities
Mark Zielinski: Author of advisory


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

Announced:     May 14, 1998
Report code:   RSI.0005.05-14-98.SUN.LIBNSL
Report title:  Sun Microsystem's libnsl
Vulnerability: Insufficient bounds checking
Vendor status: Contacted, patch under development
Patch status:  No patch available
Platforms:     Solaris 2.2, 2.3, 2.4, 2.5, 2.5.1
Vulnerable:    Several library functions in libnsl have buffer overflows
Reference:     http://www.repsec.com/advisories.html
Impact:         If exploited, an attacker could potentially compromise
               both local and remote root access on your server


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

Problem:       Several buffer overflows exist in Sun Microsystem's libnsl
               networking library.

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

         Functions we have found vulnerable:

         Vulnerable key functions:    
         ---------------------------------------------------

         extract_secret ()       : Buffer overflows while copying
           data into a local buffer
         getkeys_nis ()          : Buffer overflows if key value
                                         is larger then the buffer  
         getpublickey ()         : Calls getkeys_nis ()
         getsecretkey ()         : Calls getkeys_nis ()


         Vulnerable RPC functions:
         ----------------------------------------------------

               authdes_seccreate ()    : Calls getpublickey ()
               rpc_broadcast_exp ()    : Buffer overflow if allowed to
                 specify network protocol type
         rpc_broadcast ()        : Calls rpc_broadcast_exp ()
         clnt_create_timed ()    : Buffer overflow if allowed to
                 specify network protocol type
         host2netname ()         : Buffer overflow while specifying
                 hostname.
         getnetname ()         : Calls host2netname ()
         clnt_create ()         : Calls clnt_create_timed ()
               rpc_call ()         : Buffer overflow if allowed to
                 specify network protocol type
         authdes_pk_seccreate () : Calls getnetname ()


               Vulnerable NIS functions:
         ----------------------------------------------------

               __nis_init_callback ()  : Calls getpublickey ()
               __nis_core_lookup ()    : Buffer overflow while copying
           paramaters into a local buffer
               nis_make_rpchandle ()   : Calls host2netname ()
               nis_dump_r ()           : Calls nis_make_rpchandle ()
               nis_dump ()             : Calls nis_dump_r ()
               __nis_auth2princ ()     : Buffer overflow while specifying
           machine name
               __nis_host2nis_server (): Buffer overflow while specifying
           hostname
               nis_name_of_r ()        : Buffer overflow while copying
           paramaters into a local buffer
         nis_old_data_r ()       : Buffer overflow while copying 
                 paramaters into a local buffer
               nis_list ()         : Calls __nis_core_lookup ()
               nis_add ()         : Calls nis_nameops ()
               nis_remove ()           : Calls nis_nameops ()
               nis_modify ()         : Calls nis_nameops ()
               nis_mkdir ()         : Calls nis_make_rpchandle ()
               nis_rmdir ()         : Calls nis_make_rpchandle ()


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

               Calls vulnerable RPC functions:

           1. nfs mount
           2. nfs share
                 3. rpc.rexd
                 4. autofs
    
               Calls vulnerable key functions:
           
                 1. chkey
                 2. keylogin
                 3. setkey
                 4. newkey
                 5. keyserv
                 6. libscheme

               Calls vulnerable NIS functions:
          
                 1. rpc.nisd
                 2. rpc.nisdpasswdd
                 3. nisping
                 4. nisaddent
                 5. nisupdkeys
                 6. nisaddcred
                 7. sendmail
                 8. volcheck
                 9. vold

               Calls vulnerable YP functions:

                 1. vacation
                 2. ypwhich
                 3. yppush


         These vulnerabilities are present in Sun Microsystem's 
               Solaris 2.2, 2.3, 2.4, 2.5, and 2.5.1. 

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


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

Solution:      No fix available.


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

Solution:      Sun Microsystem's has not released an official patch.


---------------------------------------------------------------------------

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

[ http://www.repsec.com ]

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