Oracle Linux 8 : varnish:6 (ELSA-2020-4756)

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2020-4756.
##

include('compat.inc');

if (description)
{
  script_id(142772);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/05/11");

  script_cve_id("CVE-2019-15892", "CVE-2019-20637", "CVE-2020-11653");

  script_name(english:"Oracle Linux 8 : varnish:6 (ELSA-2020-4756)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
ELSA-2020-4756 advisory.

  - An issue was discovered in Varnish Cache before 6.0.4 LTS, and 6.1.x and 6.2.x before 6.2.1. An HTTP/1
    parsing failure allows a remote attacker to trigger an assert by sending crafted HTTP/1 requests. The
    assert will cause an automatic restart with a clean cache, which makes it a Denial of Service attack.
    (CVE-2019-15892)

  - An issue was discovered in Varnish Cache before 6.0.6 LTS, 6.1.x and 6.2.x before 6.2.3, and 6.3.x before
    6.3.2. It occurs when communication with a TLS termination proxy uses PROXY version 2. There can be an
    assertion failure and daemon restart, which causes a performance loss. (CVE-2020-11653)

  - An issue was discovered in Varnish Cache before 6.0.5 LTS, 6.1.x and 6.2.x before 6.2.2, and 6.3.x before
    6.3.1. It does not clear a pointer between the handling of one client request and the next request within
    the same connection. This sometimes causes information to be disclosed from the connection workspace, such
    as data structures associated with previous requests within this connection or VCL-related temporary
    headers. (CVE-2019-20637)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://linux.oracle.com/errata/ELSA-2020-4756.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:L/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:"cvss_score_source", value:"CVE-2019-20637");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/09/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/11/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/11/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:varnish");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:varnish-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:varnish-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:varnish-modules");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  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);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 8', 'Oracle Linux ' + 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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

module_ver = get_kb_item('Host/RedHat/appstream/varnish');
if (isnull(module_ver)) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module varnish:6');
if ('6' >!< module_ver) audit(AUDIT_PACKAGE_NOT_AFFECTED, 'Module varnish:' + module_ver);

appstreams = {
    'varnish:6': [
      {'reference':'varnish-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-devel-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-devel-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-docs-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-docs-6.0.6-2.module+el8.3.0+7653+45014445', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-modules-0.15.0-5.module+el8.3.0+7653+45014445', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'varnish-modules-0.15.0-5.module+el8.3.0+7653+45014445', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE}
    ]
};

flag = 0;
appstreams_found = 0;
foreach module (keys(appstreams)) {
  appstream = NULL;
  appstream_name = NULL;
  appstream_version = NULL;
  appstream_split = split(module, sep:':', keep:FALSE);
  if (!empty_or_null(appstream_split)) {
    appstream_name = appstream_split[0];
    appstream_version = appstream_split[1];
    if (!empty_or_null(appstream_name)) appstream = get_one_kb_item('Host/RedHat/appstream/' + appstream_name);
  }
  if (!empty_or_null(appstream) && appstream_version == appstream || appstream_name == 'all') {
    appstreams_found++;
    foreach package_array ( appstreams[module] ) {
      reference = NULL;
      release = NULL;
      sp = NULL;
      cpu = NULL;
      el_string = NULL;
      rpm_spec_vers_cmp = NULL;
      epoch = NULL;
      allowmaj = NULL;
      if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
      if (!empty_or_null(package_array['release'])) release = 'EL' + package_array['release'];
      if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
      if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
      if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
      if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
      if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
      if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
      if (reference && release) {
        if (rpm_check(release:release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
      }
    }
  }
}

if (!appstreams_found) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module varnish:6');

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, 'varnish / varnish-devel / varnish-docs / etc');
}