CentOS 7 : krb5 (CESA-2018:0666)

2018-04-27T00:00:00
ID CENTOS_RHSA-2018-0666.NASL
Type nessus
Reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-10-02T00:00:00

Description

An update for krb5 is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es) :

  • krb5: Authentication bypass by improper validation of certificate EKU and SAN (CVE-2017-7562)

  • krb5: Invalid S4U2Self or S4U2Proxy request causes assertion failure (CVE-2017-11368)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes :

For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.5 Release Notes linked from the References section.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Red Hat Security Advisory RHSA-2018:0666 and 
# CentOS Errata and Security Advisory 2018:0666 respectively.
#

include("compat.inc");

if (description)
{
  script_id(109370);
  script_version("1.4");
  script_cvs_date("Date: 2019/12/31");

  script_cve_id("CVE-2017-11368", "CVE-2017-7562");
  script_xref(name:"RHSA", value:"2018:0666");

  script_name(english:"CentOS 7 : krb5 (CESA-2018:0666)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote CentOS host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"An update for krb5 is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security
impact of Moderate. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.

Kerberos is a network authentication system, which can improve the
security of your network by eliminating the insecure practice of
sending passwords over the network in unencrypted form. It allows
clients and servers to authenticate to each other with the help of a
trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es) :

* krb5: Authentication bypass by improper validation of certificate
EKU and SAN (CVE-2017-7562)

* krb5: Invalid S4U2Self or S4U2Proxy request causes assertion failure
(CVE-2017-11368)

For more details about the security issue(s), including the impact, a
CVSS score, and other related information, refer to the CVE page(s)
listed in the References section.

Additional Changes :

For detailed information on changes in this release, see the Red Hat
Enterprise Linux 7.5 Release Notes linked from the References section."
  );
  # https://lists.centos.org/pipermail/centos-cr-announce/2018-April/004883.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?5c96c83a"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected krb5 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:P");
  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_attribute(attribute:"cvss_score_source", value:"CVE-2017-11368");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-pkinit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-server-ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:krb5-workstation");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libkadm5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/08/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/04/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/04/27");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"CentOS Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/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/CentOS/release");
if (isnull(release) || "CentOS" >!< release) audit(AUDIT_OS_NOT, "CentOS");
os_ver = pregmatch(pattern: "CentOS(?: Linux)? release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "CentOS");
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "CentOS 7.x", "CentOS " + os_ver);

if (!get_kb_item("Host/CentOS/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, "CentOS", cpu);


flag = 0;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-devel-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-libs-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-pkinit-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-server-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-server-ldap-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"krb5-workstation-1.15.1-18.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"libkadm5-1.15.1-18.el7")) flag++;


if (flag)
{
  cr_plugin_caveat = '\n' +
    'NOTE: The security advisory associated with this vulnerability has a\n' +
    'fixed package version that may only be available in the continuous\n' +
    'release (CR) repository for CentOS, until it is present in the next\n' +
    'point release of CentOS.\n\n' +

    'If an equal or higher package level does not exist in the baseline\n' +
    'repository for your major version of CentOS, then updates from the CR\n' +
    'repository will need to be applied in order to address the\n' +
    'vulnerability.\n';
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get() + cr_plugin_caveat
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "krb5-devel / krb5-libs / krb5-pkinit / krb5-server / etc");
}