slocate vulnerability

["Adam Gilmore" <agilmore () optusnet com au>]

Below is an advisory on a buffer overflow in slocate 2.6.1.  I can’t
replicate the same error in gdb as the advisory and I don’t believe it’s
a buffer overflow at all.
 
(gdb) run -c `perl -e "print 'A' x 1024"` -r `perl -e "print 'A' x
1024"`
Starting program: /home/drg/sl/slocate-2.6/./slocate -c `perl -e "print
'A' x 1024"` -r `perl -e "print 'A' x 1024"`
warning: slocate: decode_db(): : No such file or directory
 
Program received signal SIGSEGV, Segmentation fault.
0x40079527 in vfprintf () from /lib/libc.so.6
(gdb) bt
#0  0x40079527 in vfprintf () from /lib/libc.so.6
#1  0x4009ab43 in vsnprintf () from /lib/libc.so.6
#2  0x0804bc06 in report_error (STATUS=0, QUIET=0, format=0x804bff5 "%s:
decode_db(): %s: %s\n") at misc.c:149
#3  0x0804aa3d in decode_db (database=0x19 <Address 0x19 out of bounds>,
str=0xbffff28e 'A' <repeats 200 times>...) at main.c:1164
#4  0x0804b70f in main (args=5, argv=0xbffff144) at main.c:1549
#5  0x4003e280 in __libc_start_main () from /lib/libc.so.6
 
As far as I can see, the error is because the function report_error is
parsed the pointer database which is 0x19 (probably because the program
couldn’t get the config file or what not parsed with –c).
 
Anyone care to shed some light on the situation?
 
 
__________________________________________________ 
 
USG Security Advisory 
http://www.usg.org.uk/advisories/2003.001.txt 
inkubus () hushmail com 
USG- SA- 2003.001 24- Jan- 2003 
__________________________________________________ 
 
Package: slocate 
Vulnerability: local buffer overflow 
Type: local 
Risk: high, users can gain high privileges in the system. 
System tested: RedHat Linux 7.3 (Valhalla) with slocate-2.6-1 from RPM 
Credits: Knight420, Team TESO, Michal Zalewski, Aleph1, dvdman 
 
Description: 
Accordingly to research done by USG team members and Knight420 who
informed us 
about this vulnerability a week earlier, there is a local buffer
overflow in th
e slocate package 
shipped with the most newer RedHat distributions, we have tested the
vulnerabil
ity only in RedHat 
Linux 7.2 and 7.3 but we think that other Linux/*nix systems that
provide sloca
te package may be 
vulnerable too. 
The overflow appears when the slocate is  runned with two parameters: -c
and -r
, using as arguments a 
1024 (or 10240, as Knight420 has informed us earlier) bytes string. 
[inkubus@USG audit]$ rpm -qf /usr/bin/slocate && ls -al /usr/bin/slocate

slocate-2.6-1 
-rwxr-sr-x    1 root     slocate     25020 Jun 25  2001 /usr/bin/slocate

[inkubus@USG audit]$ /usr/bin/slocate -c `perl -e "print 'A' x 1024"` -r
`perl 
-e "print 'A' x 1024"` 
Segmentation fault 
[inkubus@USG audit]$ gdb /usr/bin/slocate 
GNU gdb Red Hat Linux (5.1.90CVS-5) 
Copyright 2002 Free Software Foundation, Inc. 
GDB is free software, covered by the GNU General Public License, and you
are 
welcome to change it and/or distribute copies of it under certain
conditions. 
Type "show copying" to see the conditions. 
There is absolutely no warranty for GDB.  Type "show warranty" for
details. 
This GDB was configured as "i386-redhat-linux"...(no debugging symbols
found)..
. 
(gdb) r -c `perl -e "print 'A' x 1024"` -r `perl -e "print 'A' x 1024"` 
Starting program: /usr/bin/slocate -c `perl -e "print 'A' x 1024"` -r
`perl -e 
"print 'A' x 1024"` 
warning: slocate: could not open database: /var/lib/slocate/slocate.db:
Permiss
ion denied 
warning: You need to run the 'updatedb' command (as root) to create the
databas
e. 
warning: slocate: decode_db(): ÐßBÐßBØßBØßBàßBàßBèßBèßBðßBðßBøßBøßB: No
such fi
le or directory 
warning: You need to run the 'updatedb' command (as root) to create the
databas
e. 
(no debugging symbols found)...(no debugging symbols found)...(no
debugging sym
bols found)... 
Program received signal SIGSEGV, Segmentation fault. 
0x42080b1b in strlen () from /lib/i686/libc.so.6 
(gdb) 
 
The exploitation is trivial, we have coded already a POC exploit that
will be p
ublished to the bugtraq 
next days. 
The author has been notified via: klindsay () mkintraweb com 
 
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inkubus () hushmail com 
Resistance is futile, you will be assimilated. 
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EOF