FreeBSD : polkit -- local privilege escalation using polkit_system_bus_name_get_creds_sync (36a35d83-c560-11eb-84ab-e0d55e2a8bf9)

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2021 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
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#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
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#    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
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# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(150314);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/27");

  script_cve_id("CVE-2021-3560");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2023/06/02");

  script_name(english:"FreeBSD : polkit -- local privilege escalation using polkit_system_bus_name_get_creds_sync (36a35d83-c560-11eb-84ab-e0d55e2a8bf9)");

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

The function polkit_system_bus_name_get_creds_sync is used to get the
uid and pid of the process requesting the action. It does this by
sending the unique bus name of the requesting process, which is
typically something like ':1.96', to dbus-daemon. These unique names
are assigned and managed by dbus-daemon and cannot be forged, so this
is a good way to check the privileges of the requesting process.

The vulnerability happens when the requesting process disconnects from
dbus-daemon just before the call to
polkit_system_bus_name_get_creds_sync starts. In this scenario, the
unique bus name is no longer valid, so dbus-daemon sends back an error
reply. This error case is handled in
polkit_system_bus_name_get_creds_sync by setting the value of the
error parameter, but it still returns TRUE, rather than FALSE. This
behavior means that all callers of
polkit_system_bus_name_get_creds_sync need to carefully check whether
an error was set. If the calling function forgets to check for errors
then it will think that the uid of the requesting process is 0
(because the AsyncGetBusNameCredsData struct is zero initialized). In
other words, it will think that the action was requested by a root
process, and will therefore allow it.");
  script_set_attribute(attribute:"see_also", value:"https://seclists.org/oss-sec/2021/q2/180");
  script_set_attribute(attribute:"see_also", value:"https://gitlab.freedesktop.org/polkit/polkit/-/commit/a04d13a");
  # https://vuxml.freebsd.org/freebsd/36a35d83-c560-11eb-84ab-e0d55e2a8bf9.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3d4c0e75");
  script_set_attribute(attribute:"solution", value:
"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3560");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Polkit D-Bus Authentication Bypass');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/06/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/06/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/06/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:polkit");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"FreeBSD Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  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:"polkit<0.119")) flag++;

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