Vulnerabilities > CVE-2019-17007 - Improper Certificate Validation vulnerability in multiple products

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
low complexity
mozilla
siemens
CWE-295
nessus

Summary

In Network Security Services before 3.44, a malformed Netscape Certificate Sequence can cause NSS to crash, resulting in a denial of service.

Vulnerable Configurations

Part Description Count
Application
Mozilla
153
OS
Siemens
8
Hardware
Siemens
8

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 familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4579.NASL
    descriptionTwo vulnerabilities were discovered in NSS, a set of cryptographic libraries, which may result in denial of service and potentially the execution of arbitrary code.
    last seen2020-06-01
    modified2020-06-02
    plugin id131784
    published2019-12-09
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/131784
    titleDebian DSA-4579-1 : nss - security update
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Debian Security Advisory DSA-4579. The text 
    # itself is copyright (C) Software in the Public Interest, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(131784);
      script_version("1.3");
      script_cvs_date("Date: 2020/01/15");
    
      script_cve_id("CVE-2019-11745", "CVE-2019-17007");
      script_xref(name:"DSA", value:"4579");
    
      script_name(english:"Debian DSA-4579-1 : nss - 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:
    "Two vulnerabilities were discovered in NSS, a set of cryptographic
    libraries, which may result in denial of service and potentially the
    execution of arbitrary code."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/source-package/nss"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/buster/nss"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://www.debian.org/security/2019/dsa-4579"
      );
      script_set_attribute(
        attribute:"solution", 
        value:
    "Upgrade the nss packages.
    
    For the stable distribution (buster), these problems have been fixed
    in version 2:3.42.1-1+deb10u2."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/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:N/UI:R/S:U/C:H/I:H/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-2019-11745");
      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:debian:debian_linux:nss");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:10.0");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/08");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/12/06");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/12/09");
      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:"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:"libnss3", reference:"2:3.42.1-1+deb10u2")) flag++;
    if (deb_check(release:"10.0", prefix:"libnss3-dev", reference:"2:3.42.1-1+deb10u2")) flag++;
    if (deb_check(release:"10.0", prefix:"libnss3-tools", reference:"2:3.42.1-1+deb10u2")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
      else security_warning(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-2015.NASL
    descriptionHandling of Netscape Certificate Sequences in CERT_DecodeCertPackage() may haved crash with a NULL deref leading to a denial of service. For Debian 8
    last seen2020-06-01
    modified2020-06-02
    plugin id131433
    published2019-12-03
    reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/131433
    titleDebian DLA-2015-1 : nss security update
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-4215-1.NASL
    descriptionIt was discovered that NSS incorrectly handled certain certificates. An attacker could possibly use this issue to cause a denial of service. 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.
    last seen2020-06-01
    modified2020-06-02
    plugin id131923
    published2019-12-10
    reporterUbuntu Security Notice (C) 2019 Canonical, Inc. / NASL script (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/131923
    titleUbuntu 16.04 LTS / 18.04 LTS / 19.04 : nss vulnerability (USN-4215-1)