FreeBSD : Mbed TLS -- Local side channel attack on classical CBC decryption in (D)TLS (4c69240f-f02c-11ea-838a-0011d823eebd)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2020 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(140312);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/21");

  script_cve_id("CVE-2020-16150");

  script_name(english:"FreeBSD : Mbed TLS -- Local side channel attack on classical CBC decryption in (D)TLS (4c69240f-f02c-11ea-838a-0011d823eebd)");

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

When decrypting/authenticating (D)TLS record in a connection using a
CBC ciphersuite without the Encrypt-then-Mac extension RFC 7366, Mbed
TLS used dummy rounds of the compression function associated with the
hash used for HMAC in order to hide the length of the padding to
remote attackers, as recommended in the original Lucky Thirteen paper.

A local attacker who is able to observe the state of the cache could
monitor the presence of mbedtls_md_process() in the cache in order to
determine when the actual computation ends and when the dummy rounds
start. This is a reliable target as it's always called at least once,
in response to a previous attack. The attacker can then continue with
one of many well-documented Lucky 13 variants.");
  # https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-09-1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b543877b");
  # https://vuxml.freebsd.org/freebsd/4c69240f-f02c-11ea-838a-0011d823eebd.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dee90615");
  script_set_attribute(attribute:"solution", value:
"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/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:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-16150");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/09/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/09/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/09/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:mbedtls");
  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) 2020-2024 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:"mbedtls<2.16.8")) 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");