This fixes a potentially exploitable buffer overrun in dtprintinfo.
This was brought to my attention based on a 0day exploit released for
Solaris CDE.
The exploit code does not work (or build) on linux, and the overrun is
in the heap rather than the stack as on Solaris, but it's easy to see
how this could be exploited.
The following is the content of the advisory:
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@Mediaservice.net (Cybaze Group) Security Advisory #2019-01 (2019-05-07)
Title: Local privilege escalation via CDE dtprintinfo
Application: Common Desktop Environment 2.3.0 and earlier
Platforms: Oracle Solaris 10 1/13 (Update 11) and earlier
Description: A local attacker can gain root privileges by exploiting
a buffer overflow in CDE dtprintinfo
Author: Marco Ivaldi <marco.ivaldi@mediaservice.net>
Contributor: Dave Aitel <dave.aitel@cyxtera.com> (original discovery)
Vendor Status: <secalert_us@oracle.com> notified on 2019-05-05
<cdesktopenv-devel@lists.sourceforge.net> notified on 2019-05-05
CVE: The Common Vulnerabilities and Exposures project has not assigned
a name to this issue yet
References: https://lab.mediaservice.net/advisory/2019-01-cde-dtprintinfo.txthttps://github.com/0xdea/raptor_infiltrate19https://sourceforge.net/p/cdesktopenv/wiki/Home/https://www.oracle.com/technetwork/server-storage/solaris10/https://www.mediaservice.net/https://infiltratecon.com/
1. Abstract.
A buffer overflow in the DtPrinterAction::PrintActionExists() function in the
Common Desktop Environment 2.3.0 and earlier, as used in Oracle Solaris 10 1/13
(Update 11) and earlier, allows local users to gain root privileges via a long
printer name passed to dtprintinfo by a malicious lpstat program.
This is a 0day vulnerability demonstrated at #INFILTRATE19 on May 2nd, 2019 in
the talk "A bug's life: story of a Solaris 0day".
2. Example Attack Session.
bash-3.2$ cat /etc/release
Oracle Solaris 10 1/13 s10x_u11wos_24a X86
Copyright (c) 1983, 2013, Oracle and/or its affiliates. All rights reserved.
Assembled 17 January 2013
bash-3.2$ uname -a
SunOS nostalgia 5.10 Generic_147148-26 i86pc i386 i86pc
bash-3.2$ id
uid=54322(raptor) gid=1(other)
bash-3.2$ gcc raptor_dtprintname_intel.c -o raptor_dtprintname_intel -Wall
bash-3.2$ ./raptor_dtprintname_intel 192.168.1.1:0
raptor_dtprintname_intel.c - dtprintinfo 0day, Solaris/Intel
Copyright (c) 2004-2019 Marco Ivaldi <raptor@0xdeadbeef.info>
Using SI_PLATFORM : i86pc (5.10)
Using stack base : 0x8047fff
Using rwx_mem address : 0xfeffa004
Using sc address : 0x8047f60
Using strcpy() address : 0xfefe26a0
lpstat called with -v
lpstat called with -v
lpstat called with -d
uid=0(root) gid=1(other)
3. Affected Platforms.
All platforms shipping the Common Desktop Environment are potentially
affected. This includes:
* Oracle Solaris 10 1/13 (Update 11) and earlier [default installation]
According to the CDE Wiki, the following platforms are officially supported:
* All Official Ubuntu variants 12.04 - 18.04
* Debian 6, 7, 8, 9
* Fedora 17 at least
* Archlinux
* Red Hat
* Slackware 14.0
* OpenBSD
* NetBSD
* FreeBSD 9.2, 10.x, 11.x
* openSUSE Tumbleweed (gcc7)
* openSUSE Leap 4.2 (gcc4)
* SUSE 12 SP3 (gcc4)
* Solaris, OpenIndiana
4. Fix.
The upstream CDE maintainers have issued a patch for this vulnerability. Oracle
is investigating the issue via tracking# S1153109 and is expected to release a
fix for all affected-supported versions of Solaris via their quarterly Critical
Patch Update (CPU) program.
As a temporary workaround, it is possible to remove the setuid bit from the
dtprintinfo executable as follows:
bash-3.2# chmod -s /usr/dt/bin/dtprintinfo
5. Proof of Concept.
A working exploit for Oracle Solaris 10 1/13 (Update 11) Intel has been
developed as a proof of concept. Exploits for other Solaris versions and for
the SPARC architecture are also available. All exploits can be downloaded at:
https://github.com/0xdea/raptor_infiltrate19/https://github.com/0xdea/exploits/
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dtcalc compiled with clang segfaulted when switched
to a different mode like Deg to Rad or Financial to
Scientific. Was reproducable at least under FreeBSD/AMD64.
Fixed now.
In this commit, we convert FreeBSD and OpenBSD to use a system version
of TCL (8.6).
We also get rid of the hairy and buggy "CompareI18NStrings" custom Tcl
function and use the newer Tcl's builtin dictionary sort mechanism for
generating the Indexes and Glossaries, which were silently broken in
previous commits.
It was just not possible to use the same Tcl code in modern versions
of Tcl in addition to the ancient version included with CDE - so, now
we will always depend on the system version. It's been tested with
8.6 and 8.7 versions of Tcl with great results.
dtdocbook/instant has been modified to use a more modern Tcl (8.6),
which means certain functions are not present when we are using the
dtdocbook/tcl (7.5) version of tcl instead of a modern system version.
So, create some defines that should work around this problem.
One issue that came up was attempting to read array values indexed by
a key that didn't exist when generating indexes and glossaries.
I am not sure why this hasn't been a problem before, but for now, we
simply won't try to emit array values for non-existant array indexes.
Remove calls to bogus utility functions in cases where the user is
root and the filesystem in question is an NFS filesystem.
For now, __linux___ and CSRG_BASED machines will use statfs to
determine whether to test delete-ability. For other systems, just do
the create/delete test always if the user is root.
dtfile makes use of ustat(2) on certain systems. This call has been
deprecated in glibc for a while and now, as of glibc-2.28, it has been
removed. The recommended replacement is to use statfs(2).
Jon Trulson