Vulnerabilities > CVE-2020-7043 - Improper Certificate Validation vulnerability in multiple products

047910
CVSS 9.1 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
NONE
network
low complexity
openfortivpn-project
fedoraproject
opensuse
CWE-295
critical
nessus
NVD
Published: 2020-02-27
Updated: 2024-11-21

Summary

An issue was discovered in openfortivpn 1.11.0 when used with OpenSSL before 1.0.2. tunnel.c mishandles certificate validation because hostname comparisons do not consider '\0' characters, as demonstrated by a good.example.com\x00evil.example.com attack.

Vulnerable Configurations

Part Description Count
Application
Openfortivpn_Project
20
Application
Openssl
1
Application
Opensuse
1
OS
Fedoraproject
3
OS
Opensuse
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Creating a Rogue Certificate Authority Certificate
    An attacker exploits a weakness in the MD5 hash algorithm (weak collision resistance) to generate a certificate signing request (CSR) that contains collision blocks in the "to be signed" part. The attacker specially crafts two different, but valid X.509 certificates that when hashed with the MD5 algorithm would yield the same value. The attacker then sends the CSR for one of the certificates to the Certification Authority which uses the MD5 hashing algorithm. That request is completely valid and the Certificate Authority issues an X.509 certificate to the attacker which is signed with its private key. An attacker then takes that signed blob and inserts it into another X.509 certificate that the attacker generated. Due to the MD5 collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the attackers' second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority. To make the attack more interesting, the second certificate could be not just a regular certificate, but rather itself a signing certificate. Thus the attacker is able to start their own Certification Authority that is anchored in its root of trust in the legitimate Certification Authority that has signed the attackers' first X.509 certificate. If the original Certificate Authority was accepted by default by browsers, so will now the Certificate Authority set up by the attacker and of course any certificates that it signs. So the attacker is now able to generate any SSL certificates to impersonate any web server, and the user's browser will not issue any warning to the victim. This can be used to compromise HTTPS communications and other types of systems where PKI and X.509 certificates may be used (e.g., VPN, IPSec) .

Nessus

  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2020-301.NASL
    descriptionThis update for openfortivpn to version 1.12.0 fixes the following issues : - CVE-2020-7043: Fixed a TLS Certificate CommonName NULL Byte Vulnerability (boo#1165301). - CVE-2020-7042: Fixed use of uninitialized memory in X509_check_host (boo#1165300). - CVE-2020-7041: Fixed incorrect use of X509_check_host (boo#1165299).
    last seen2020-03-18
    modified2020-03-06
    plugin id134282
    published2020-03-06
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134282
    titleopenSUSE Security Update : openfortivpn (openSUSE-2020-301)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from openSUSE Security Update openSUSE-2020-301.
#
# The text description of this plugin is (C) SUSE LLC.
#

include("compat.inc");

if (description)
{
  script_id(134282);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/10");

  script_cve_id("CVE-2020-7041", "CVE-2020-7042", "CVE-2020-7043");

  script_name(english:"openSUSE Security Update : openfortivpn (openSUSE-2020-301)");
  script_summary(english:"Check for the openSUSE-2020-301 patch");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote openSUSE host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"This update for openfortivpn to version 1.12.0 fixes the following
issues :

  - CVE-2020-7043: Fixed a TLS Certificate CommonName NULL
    Byte Vulnerability (boo#1165301).

  - CVE-2020-7042: Fixed use of uninitialized memory in
    X509_check_host (boo#1165300).

  - CVE-2020-7041: Fixed incorrect use of X509_check_host
    (boo#1165299)."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1165299"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1165300"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1165301"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected openfortivpn packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N");
  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:N/UI:N/S:U/C:H/I:H/A:N");
  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:novell:opensuse:openfortivpn");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:openfortivpn-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:openfortivpn-debugsource");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:15.1");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/03/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/03/06");
  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:"SuSE Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/SuSE/release", "Host/SuSE/rpm-list", "Host/cpu");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/SuSE/release");
if (isnull(release) || release =~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "openSUSE");
if (release !~ "^(SUSE15\.1)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "15.1", release);
if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

ourarch = get_kb_item("Host/cpu");
if (!ourarch) audit(AUDIT_UNKNOWN_ARCH);
if (ourarch !~ "^(x86_64)$") audit(AUDIT_ARCH_NOT, "x86_64", ourarch);

flag = 0;

if ( rpm_check(release:"SUSE15.1", reference:"openfortivpn-1.12.0-lp151.2.5.1") ) flag++;
if ( rpm_check(release:"SUSE15.1", reference:"openfortivpn-debuginfo-1.12.0-lp151.2.5.1") ) flag++;
if ( rpm_check(release:"SUSE15.1", reference:"openfortivpn-debugsource-1.12.0-lp151.2.5.1") ) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openfortivpn / openfortivpn-debuginfo / openfortivpn-debugsource");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2020-C96AB3C813.NASL
    descriptionUpdate to latest upstream version to fix CVE-2020-7041, CVE-2020-7042 and CVE-2020-7043. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-03-18
    modified2020-03-06
    plugin id134254
    published2020-03-06
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134254
    titleFedora 31 : openfortivpn (2020-c96ab3c813)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2020-c96ab3c813.
#

include("compat.inc");

if (description)
{
  script_id(134254);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/10");

  script_cve_id("CVE-2020-7041", "CVE-2020-7042", "CVE-2020-7043");
  script_xref(name:"FEDORA", value:"2020-c96ab3c813");

  script_name(english:"Fedora 31 : openfortivpn (2020-c96ab3c813)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Update to latest upstream version to fix CVE-2020-7041, CVE-2020-7042
and CVE-2020-7043.

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2020-c96ab3c813"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected openfortivpn package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N");
  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:N/UI:N/S:U/C:H/I:H/A:N");
  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:fedoraproject:fedora:openfortivpn");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:31");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/02/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/03/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/03/06");
  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:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^31([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 31", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) 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, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC31", reference:"openfortivpn-1.12.0-1.fc31")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openfortivpn");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2020-42EB8821DB.NASL
    descriptionUpdate to latest upstream version to fix CVE-2020-7041, CVE-2020-7042 and CVE-2020-7043. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-03-18
    modified2020-03-06
    plugin id134251
    published2020-03-06
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134251
    titleFedora 30 : openfortivpn (2020-42eb8821db)

References