Amazon Linux AMI : rpm (ALAS-2021-1521)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2021-1521.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(151512);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/07/13");

  script_cve_id("CVE-2021-3421", "CVE-2021-20271");
  script_xref(name:"ALAS", value:"2021-1521");

  script_name(english:"Amazon Linux AMI : rpm (ALAS-2021-1521)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of rpm installed on the remote host is prior to 4.11.3-40.79. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS-2021-1521 advisory.

  - A flaw was found in RPM's signature check functionality when reading a package file. This flaw allows an
    attacker who can convince a victim to install a seemingly verifiable package, whose signature header was
    modified, to cause RPM database corruption and execute code. The highest threat from this vulnerability is
    to data integrity, confidentiality, and system availability. (CVE-2021-20271)

  - A flaw was found in the RPM package in the read functionality. This flaw allows an attacker who can
    convince a victim to install a seemingly verifiable package or compromise an RPM repository, to cause RPM
    database corruption. The highest threat from this vulnerability is to data integrity. This flaw affects
    RPM versions before 4.17.0-alpha. (CVE-2021-3421)

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://alas.aws.amazon.com/ALAS-2021-1521.html");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-20271");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-3421");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update rpm' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/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:L/AC:H/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-2021-20271");

  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:"2021/03/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/07/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/07/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-apidocs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-build");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-build-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-cron");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-python26");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-python27");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:rpm-sign");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2021 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);

pkgs = [
    {'reference':'rpm-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-apidocs-4.11.3-40.79.amzn1', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-build-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-build-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-build-libs-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-build-libs-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-cron-4.11.3-40.79.amzn1', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-debuginfo-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-debuginfo-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-devel-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-devel-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-libs-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-libs-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-python26-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-python26-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-python27-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-python27-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-sign-4.11.3-40.79.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'rpm-sign-4.11.3-40.79.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];

flag = 0;
foreach package_array ( pkgs ) {
  reference = NULL;
  release = NULL;
  cpu = NULL;
  el_string = NULL;
  rpm_spec_vers_cmp = NULL;
  allowmaj = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = package_array['release'];
  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['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (reference && release) {
    if (rpm_check(release:release, cpu:cpu, reference:reference, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
  }
}

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, "rpm / rpm-apidocs / rpm-build / etc");
}