FreeBSD : Xorg server -- two vulnerabilities in X server lock handling code (8441957c-f9b4-11e0-a78a-bcaec565249c)

2011-10-19T00:00:00
ID FREEBSD_PKG_8441957CF9B411E0A78ABCAEC565249C.NASL
Type nessus
Reporter Tenable
Modified 2018-11-10T00:00:00

Description

Matthieu Herrb reports :

It is possible to deduce if a file exists or not by exploiting the way that Xorg creates its lock files. This is caused by the fact that the X server is behaving differently if the lock file already exists as a symbolic link pointing to an existing or non-existing file.

It is possible for a non-root user to set the permissions for all users on any file or directory to 444, giving unwanted read access or causing denies of service (by removing execute permission). This is caused by a race between creating the lock file and setting its access modes.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2018 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
# 
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include("compat.inc");

if (description)
{
  script_id(56548);
  script_version("1.5");
  script_cvs_date("Date: 2018/11/10 11:49:42");

  script_cve_id("CVE-2011-4028", "CVE-2011-4029");

  script_name(english:"FreeBSD : Xorg server -- two vulnerabilities in X server lock handling code (8441957c-f9b4-11e0-a78a-bcaec565249c)");
  script_summary(english:"Checks for updated package in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote FreeBSD host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Matthieu Herrb reports :

It is possible to deduce if a file exists or not by exploiting the way
that Xorg creates its lock files. This is caused by the fact that the
X server is behaving differently if the lock file already exists as a
symbolic link pointing to an existing or non-existing file.

It is possible for a non-root user to set the permissions for all
users on any file or directory to 444, giving unwanted read access or
causing denies of service (by removing execute permission). This is
caused by a race between creating the lock file and setting its access
modes."
  );
  # https://vuxml.freebsd.org/freebsd/8441957c-f9b4-11e0-a78a-bcaec565249c.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?0c0099c5"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:P/I:N/A:N");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:xorg-server");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2011/10/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2011/10/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2011/10/19");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2011-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"FreeBSD Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


include("audit.inc");
include("freebsd_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (pkg_test(save_report:TRUE, pkg:"xorg-server<1.7.7_3")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_note(port:0, extra:pkg_report_get());
  else security_note(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");