FreeBSD : sudo -- Secure path vulnerability (d42e5b66-6ea0-11df-9c8d-00e0815b8da8)

2010-06-03T00:00:00
ID FREEBSD_PKG_D42E5B666EA011DF9C8D00E0815B8DA8.NASL
Type nessus
Reporter Tenable
Modified 2013-06-22T00:00:00

Description

Todd Miller reports :

Most versions of the C library function getenv() return the first instance of an environment variable to the caller. However, some programs, notably the GNU Bourne Again SHell (bash), do their own environment parsing and may choose the last instance of a variable rather than the first one.

An attacker may manipulate the environment of the process that executes Sudo such that a second PATH variable is present. When Sudo runs a bash script, it is this second PATH variable that is used by bash, regardless of whether or not Sudo has overwritten the first instance of PATH. This may allow an attacker to subvert the program being run under Sudo and execute commands he/she would not otherwise be allowed to run.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2013 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(46792);
  script_version("$Revision: 1.6 $");
  script_cvs_date("$Date: 2013/06/22 00:10:43 $");

  script_cve_id("CVE-2010-1646");

  script_name(english:"FreeBSD : sudo -- Secure path vulnerability (d42e5b66-6ea0-11df-9c8d-00e0815b8da8)");
  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:
"Todd Miller reports :

Most versions of the C library function getenv() return the first
instance of an environment variable to the caller. However, some
programs, notably the GNU Bourne Again SHell (bash), do their own
environment parsing and may choose the last instance of a variable
rather than the first one.

An attacker may manipulate the environment of the process that
executes Sudo such that a second PATH variable is present. When Sudo
runs a bash script, it is this second PATH variable that is used by
bash, regardless of whether or not Sudo has overwritten the first
instance of PATH. This may allow an attacker to subvert the program
being run under Sudo and execute commands he/she would not otherwise
be allowed to run."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"http://sudo.ws/sudo/alerts/secure_path.html"
  );
  # http://www.freebsd.org/ports/portaudit/d42e5b66-6ea0-11df-9c8d-00e0815b8da8.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?42530b87"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:C/I:C/A:C");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2010/06/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2010/06/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2010/06/03");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2010-2013 Tenable Network Security, Inc.");
  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:"sudo<1.7.2.7")) flag++;

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