Vulnerabilities > CVE-2020-7247 - Improper Handling of Exceptional Conditions vulnerability in multiple products

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4268-1. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(133522);
  script_version("1.3");
  script_cvs_date("Date: 2020/02/12");

  script_cve_id("CVE-2020-7247");
  script_xref(name:"USN", value:"4268-1");

  script_name(english:"Ubuntu 18.04 LTS / 19.10 : OpenSMTPD vulnerability (USN-4268-1)");
  script_summary(english:"Checks dpkg output for updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Ubuntu host is missing a security-related patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"It was discovered that OpenSMTPD incorrectly verified the sender's or
receiver's e-mail addresses under certain conditions. An attacker
could use this vulnerability to execute arbitrary commands as root.

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://usn.ubuntu.com/4268-1/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected opensmtpd package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'OpenSMTPD MAIL FROM Remote Code Execution');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:opensmtpd");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.10");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/02/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/06");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(18\.04|19\.10)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 18.04 / 19.10", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"18.04", pkgname:"opensmtpd", pkgver:"6.0.3p1-1ubuntu0.1")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"opensmtpd", pkgver:"6.0.3p1-6ubuntu0.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "opensmtpd");
}

#
# (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(133327);
  script_version("1.5");
  script_cvs_date("Date: 2020/02/12");

  script_cve_id("CVE-2020-7247");

  script_name(english:"FreeBSD : OpenSMTPd -- critical LPE / RCE vulnerability (08f5c27d-4326-11ea-af8b-00155d0a0200)");
  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:
"OpenSMTPD developers report :

An incorrect check allows an attacker to trick mbox delivery into
executing arbitrary commands as root and lmtp delivery into executing
arbitrary commands as an unprivileged user"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.openwall.com/lists/oss-security/2020/01/28/3"
  );
  # https://vuxml.freebsd.org/freebsd/08f5c27d-4326-11ea-af8b-00155d0a0200.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?a356904a"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-7247");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'OpenSMTPD MAIL FROM Remote Code Execution');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/01/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/01/30");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 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:"opensmtpd>=6.4.0,1<6.6.2,1")) 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");

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-4611. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(133326);
  script_version("1.5");
  script_cvs_date("Date: 2020/02/13");

  script_cve_id("CVE-2020-7247");
  script_xref(name:"DSA", value:"4611");

  script_name(english:"Debian DSA-4611-1 : opensmtpd - security update");
  script_summary(english:"Checks dpkg output for the updated package");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Qualys discovered that the OpenSMTPD SMTP server performed
insufficient validation of email addresses which could result in the
execution of arbitrary commands as root. In addition this update fixes
a denial of service by triggering an opportunistic TLS downgrade."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=950121"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/opensmtpd"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2020/dsa-4611"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the opensmtpd packages.

For the oldstable distribution (stretch), these problems have been
fixed in version 6.0.2p1-2+deb9u2.

For the stable distribution (buster), these problems have been fixed
in version 6.0.3p1-5+deb10u3. This update also includes non-security
bugfixes which were already lined up for the Buster 10.3 point
release."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-7247");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'OpenSMTPD MAIL FROM Remote Code Execution');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:opensmtpd");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:10.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/01/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/01/30");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Debian Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}


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


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (deb_check(release:"10.0", prefix:"opensmtpd", reference:"6.0.3p1-5+deb10u3")) flag++;
if (deb_check(release:"9.0", prefix:"opensmtpd", reference:"6.0.2p1-2+deb9u2")) flag++;

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

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

include('compat.inc');

if (description)
{
  script_id(133717);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/14");

  script_cve_id("CVE-2020-7247");

  script_name(english:"OpenSMTPD Critical LPE / RCE Vulnerability Remote Check");

  script_set_attribute(attribute:"synopsis", value:
"The remote mail server is affected by a LPE / RCE Vulnerability.");
  script_set_attribute(attribute:"description", value:
"A remote code execution vulnerability exists in OpenSMTPD 
 due to unsanitized email inputs. An unauthenticated, 
 remote attacker can exploit this to bypass authentication 
 and execute arbitrary commands with root privileges.");
  script_set_attribute(attribute:"see_also", value:"https://www.openwall.com/lists/oss-security/2020/01/28/3");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2020-7247");
  script_set_attribute(attribute:"see_also", value:"https://www.openbsd.org/errata66.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected opensmtpd package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-7247");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'OpenSMTPD MAIL FROM Remote Code Execution');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/01/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/02/14");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:openbsd:opensmtpd");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"SMTP problems");

  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("find_service1.nasl", "smtpserver_detect.nasl");
  script_require_ports("Services/smtp", 25);

  exit(0);
}

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

port = get_service(svc:"smtp", default:25, exit_on_fail:TRUE);

banner = get_kb_item_or_exit("smtp/banner/" + port);
if ("ESMTP OpenSMTPD" >!< banner) audit(AUDIT_NOT_LISTEN, "OpenSMTPD", port);

soc = open_sock_tcp(port);
if (!soc) audit(AUDIT_SOCK_FAIL, port);

timeout = get_kb_item("smtp/"+port+"/greetpause");
if (isnull(timeout)) timeout = 30;
socket_set_timeout(socket:soc, timeout:timeout);

hostname = get_kb_item('smtp/'+ port + '/helo');
if (!hostname) hostname = 'nessus';

banner = smtp_recv_line(socket:soc, code:"220");

if ("OpenSMTPD" >!< banner)
{
  close(soc);
  audit(AUDIT_NOT_LISTEN, "OpenSMTPD", port);
}

send(socket:soc, data:'HELO nessus\r\n');
var res = smtp_recv_line(socket:soc, code:"250");

if (empty_or_null(res) || 'pleased to meet you' >!< res)
{
  close(soc);
  exit(1, "The SMTP server on port " + port + " didn't respond to 'HELO'.");
}

send(socket:soc, data:'MAIL FROM:<;echo "This OpenSMTPD is Vulnerable to Command Insertion";>\r\n');
res = smtp_recv_line(socket:soc, code:"250");

if (empty_or_null(res) || 'error' >< res || 'Error' >< res || 'syntax' >< res )
{
  close(soc);
  exit(1, "The OpenSMTP server on port " + port + " did not accept email address, therefore, it is not vulnerable");
}

close(soc);
report =
  '\nNessus was able to confirm the vulnerability by sending a specially crafted MAIL FROM command to the remote smtp server.\n';
security_report_v4(port:port, extra:report, severity:SECURITY_HOLE);