Vulnerabilities > CVE-2019-7251 - Integer Overflow or Wraparound vulnerability in Digium Asterisk

#
# (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(122572);
  script_version("1.3");
  script_cvs_date("Date: 2020/02/07");

  script_cve_id("CVE-2019-7251");

  script_name(english:"FreeBSD : asterisk -- Remote crash vulnerability with SDP protocol violation (be0e3817-3bfe-11e9-9cd6-001999f8d30b)");
  script_summary(english:"Checks for updated packages in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote FreeBSD host is missing one or more security-related
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The Asterisk project reports :

When Asterisk makes an outgoing call, a very specific SDP protocol
violation by the remote party can cause Asterisk to crash."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://downloads.asterisk.org/pub/security/AST-2019-001.html"
  );
  # https://vuxml.freebsd.org/freebsd/be0e3817-3bfe-11e9-9cd6-001999f8d30b.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?9565e484"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:asterisk15");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:asterisk16");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/01/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/03/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/03/04");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 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:"asterisk15<15.7.2")) flag++;
if (pkg_test(save_report:TRUE, pkg:"asterisk16<16.2.1")) 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");

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(122670);
  script_version("1.2");
  script_cvs_date("Date: 2019/10/31 15:18:51");

  script_cve_id("CVE-2019-7251");
  script_bugtraq_id(107212);

  script_name(english:"Asterisk 15.x < 15.7.2 / 16.x < 16.2.1 DoS (AST-2019-001)");
  script_summary(english:"Checks the version in the SIP banner.");

  script_set_attribute(attribute:"synopsis", value:
"A telephony application running on the remote host is affected by a
denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its SIP banner, the version of Asterisk running on the
remote host is 15.x prior to 15.7.2, 16.x prior to 16.2.1. It is
therefore, affected by an error related to handling SDP traffic and
RTP negotiation described in AST-2019-001. This error allows denial
of service attacks.

Note that Nessus has not tested for these issues but has instead
relied only on the application's self-reported version number.");
  script_set_attribute(attribute:"see_also", value:"http://downloads.asterisk.org/pub/security/AST-2019-001.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Asterisk version 15.7.2 / 16.2.1 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-7251");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/01/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/01/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/03/08");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:digium:asterisk");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("asterisk_detection.nasl");
  script_require_keys("asterisk/sip_detected", "Settings/ParanoidReport");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("lists.inc");

get_kb_item_or_exit("asterisk/sip_detected");

asterisk_kbs = get_kb_list_or_exit("sip/asterisk/*/version");

if (report_paranoia < 2) audit(AUDIT_PARANOID);

is_vuln = FALSE;
not_vuln_installs = make_list();
errors = make_list();

foreach kb_name (keys(asterisk_kbs))
{
  vulnerable = 0;

  matches = pregmatch(pattern:"/(udp|tcp)/([0-9]+)/version", string:kb_name);
  if (isnull(matches))
  {
    collib::push("Unexpected error parsing port number from '"+kb_name+"'.", errors);
    continue;
  }

  proto = matches[1];
  port  = matches[2];
  version = asterisk_kbs[kb_name];

  if (version == 'unknown')
  {
    collib::push("Unable to obtain version of installation on " + proto + "/" + port + ".", errors);
    continue;
  }

  banner = get_kb_item("sip/asterisk/" + proto + "/" + port + "/source");
  if (!banner)
  {
    # We have version but banner is missing;
    # log error and use in version-check though.
    collib::push("KB item 'sip/asterisk/" + proto + "/" + port + "/source' is missing.", errors);
    banner = 'unknown';
  }

  if (version =~ "^15([^0-9])" && "cert" >!< tolower(version))
  {
    fixed = "15.7.2";
    vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
  }
  else if (version =~ "^16([^0-9])" && "cert" >!< tolower(version))
  {
    fixed = "16.2.1";
    vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
  }

  if (vulnerable < 0)
  {
    is_vuln = TRUE;
    report =
        '\n  Version source    : ' + banner +
        '\n  Installed version : ' + version +
        '\n  Fixed version     : ' + fixed +
        '\n';
      security_report_v4(severity:SECURITY_WARNING, port:port, proto:proto, extra:report);
  }
  else collib::push(version + " on port " + proto + "/" + port, not_vuln_installs);
}

if (max_index(errors))
{
  if (max_index(errors) == 1) errmsg = errors[0];
  else errmsg = 'Errors were encountered verifying installations : \n  ' + join(errors, sep:'\n  ');

  exit(1, errmsg);
}
else
{
  installs = max_index(not_vuln_installs);
  if (installs == 0)
  {
    if (is_vuln) exit(0);
    else audit(AUDIT_NOT_INST, "Asterisk");
  }
  else audit(AUDIT_INST_VER_NOT_VULN, "Asterisk", not_vuln_installs);
}