Vulnerabilities > CVE-2020-13614 - Improper Certificate Validation vulnerability in multiple products

047910
CVSS 5.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
NONE
Availability impact
NONE
network
high complexity
axel-project
fedoraproject
opensuse
CWE-295
nessus
NVD
Published: 2020-05-26
Updated: 2023-11-07

Summary

An issue was discovered in ssl.c in Axel before 2.17.8. The TLS implementation lacks hostname verification.

Vulnerable Configurations

Part Description Count
Application
Axel_Project
41
Application
Opensuse
1
OS
Fedoraproject
2
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-2020-778.NASL
descriptionThis update for axel fixes the following issues : axel was updated to 2.17.8 : - CVE-2020-13614: SSL Certificate Hostnames were not verified (boo#1172159) - Replaced progressbar line clearing with terminal control sequence - Fixed parsing of Content-Disposition HTTP header - Fixed User-Agent HTTP header never being included Update to version 2.17.7 : - Buildsystem fixes - Fixed release date for man-pages on BSD - Explicitly close TCP sockets on SSL connections too - Fixed HTTP basic auth header generation - Changed the default progress report to
last seen2020-06-11
modified2020-06-08
plugin id137227
published2020-06-08
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/137227
titleopenSUSE Security Update : axel (openSUSE-2020-778)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from openSUSE Security Update openSUSE-2020-778.
#
# The text description of this plugin is (C) SUSE LLC.
#

include("compat.inc");

if (description)
{
  script_id(137227);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/10");

  script_cve_id("CVE-2020-13614");

  script_name(english:"openSUSE Security Update : axel (openSUSE-2020-778)");
  script_summary(english:"Check for the openSUSE-2020-778 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 axel fixes the following issues :

axel was updated to 2.17.8 :

  - CVE-2020-13614: SSL Certificate Hostnames were not
    verified (boo#1172159)

  - Replaced progressbar line clearing with terminal control
    sequence

  - Fixed parsing of Content-Disposition HTTP header

  - Fixed User-Agent HTTP header never being included

Update to version 2.17.7 :

  - Buildsystem fixes

  - Fixed release date for man-pages on BSD

  - Explicitly close TCP sockets on SSL connections too

  - Fixed HTTP basic auth header generation

  - Changed the default progress report to 'alternate output
    mode'

  - Improved English in README.md

Update to version 2.17.6 :

  - Fixed handling of non-recoverable HTTP errors

  - Cleanup of connection setup code

  - Fixed manpage reproducibility issue

  - Use tracker instead of PTS from Debian

Update to version 2.17.5 :

  - Fixed progress indicator misalignment

  - Cleaned up the wget-like progress output code

  - Improved progress output flushing

Update to version 2.17.4 :

  - Fixed build with bionic libc (Android)

  - TCP Fast Open support on Linux

  - TCP code cleanup

  - Removed dependency on libm

  - Data types and format strings cleanup

  - String handling cleanup

  - Format string checking GCC attributes added

  - Buildsystem fixes and improvements

  - Updates to the documentation

  - Updated all translations

  - Fixed Footnotes in documentation

  - Fixed a typo in README.md

Update to version 2.17.3 :

  - Builds now use canonical host triplet instead of `uname
    -s`

  - Fixed build on Darwin / Mac OS X

  - Fixed download loops caused by last byte pointer being
    off by one

  - Fixed linking issues (i18n and posix threads)

  - Updated build instructions

  - Code cleanup

  - Added autoconf-archive to building instructions

Update to version 2.17.2 :

  - Fixed HTTP request-ranges to be zero-based

  - Fixed typo 'too may' -> 'too many'

  - Replaced malloc + memset calls with calloc

  - Sanitize progress bar buffer len passed to memset

Update to version 2.17.1 :

  - Fixed comparison error in axel_divide

  - Make sure maxconns is at least 1

Update to version 2.17 :

  - Fixed composition of URLs in redirections

  - Fixed request range calculation

  - Updated all translations

  - Updated build documentation

  - Major code cleanup

  - Cleanup of alternate progress output

  - Removed global string buffers

  - Fixed min and max macros

  - Moved User-Agent header to conf->add_header

  - Use integers for speed ratio and delay calculation

  - Added support for parsing IPv6 literal hostname

  - Fixed filename extraction from URL

  - Fixed request-target message to proxy

  - Handle secure protocol's schema even with SSL disabled

  - Fixed Content-Disposition filename value decoding

  - Strip leading hyphens in extracted filenames"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.opensuse.org/show_bug.cgi?id=1172159"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected axel packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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:N/AC:H/PR:N/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:"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:axel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:axel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:axel-debugsource");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:15.1");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/05/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/06/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/06/08");
  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:"axel-2.17.8-lp151.3.3.1") ) flag++;
if ( rpm_check(release:"SUSE15.1", reference:"axel-debuginfo-2.17.8-lp151.3.3.1") ) flag++;
if ( rpm_check(release:"SUSE15.1", reference:"axel-debugsource-2.17.8-lp151.3.3.1") ) 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, "axel / axel-debuginfo / axel-debugsource");
}

References