Amazon Linux AMI : unbound (ALAS-2020-1373)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2020-1373.
#

include('compat.inc');

if (description)
{
  script_id(137096);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/03/08");

  script_cve_id("CVE-2020-12662", "CVE-2020-12663");
  script_xref(name:"ALAS", value:"2020-1373");

  script_name(english:"Amazon Linux AMI : unbound (ALAS-2020-1373)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"A network amplification vulnerability was found in Unbound, in the way
it processes delegation messages from one authoritative zone to
another. This flaw allows an attacker to cause a denial of service or
be part of an attack against another DNS server when Unbound is
deployed as a recursive resolver or authoritative name
server.(CVE-2020-12662)

Unbound before 1.10.1 has an infinite loop via malformed DNS answers
received from upstream servers.(CVE-2020-12663)");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/ALAS-2020-1373.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update unbound' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:N/S:U/C:N/I:N/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-2020-12663");

  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:"2020/05/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/06/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/06/04");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:unbound-python");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/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/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (rpm_check(release:"ALA", reference:"unbound-1.6.6-1.5.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"unbound-debuginfo-1.6.6-1.5.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"unbound-devel-1.6.6-1.5.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"unbound-libs-1.6.6-1.5.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"unbound-python-1.6.6-1.5.amzn1")) 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, "unbound / unbound-debuginfo / unbound-devel / unbound-libs / etc");
}