Amazon Linux AMI : openssl (ALAS-2023-1762)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2023-1762.
##

include('compat.inc');

if (description)
{
  script_id(177069);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/08/10");

  script_cve_id(
    "CVE-2023-0464",
    "CVE-2023-0465",
    "CVE-2023-0466",
    "CVE-2023-2650"
  );
  script_xref(name:"IAVA", value:"2023-A-0158-S");

  script_name(english:"Amazon Linux AMI : openssl (ALAS-2023-1762)");

  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 openssl installed on the remote host is prior to 1.0.2k-16.163. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS-2023-1762 advisory.

  - A security vulnerability has been identified in all supported versions of OpenSSL related to the
    verification of X.509 certificate chains that include policy constraints. Attackers may be able to exploit
    this vulnerability by creating a malicious certificate chain that triggers exponential use of
    computational resources, leading to a denial-of-service (DoS) attack on affected systems. Policy
    processing is disabled by default but can be enabled by passing the `-policy' argument to the command line
    utilities or by calling the `X509_VERIFY_PARAM_set1_policies()' function. (CVE-2023-0464)

  - Applications that use a non-default option when verifying certificates may be vulnerable to an attack from
    a malicious CA to circumvent certain checks. Invalid certificate policies in leaf certificates are
    silently ignored by OpenSSL and other certificate policy checks are skipped for that certificate. A
    malicious CA could use this to deliberately assert invalid certificate policies in order to circumvent
    policy checking on the certificate altogether. Policy processing is disabled by default but can be enabled
    by passing the `-policy' argument to the command line utilities or by calling the
    `X509_VERIFY_PARAM_set1_policies()' function. (CVE-2023-0465)

  - The function X509_VERIFY_PARAM_add0_policy() is documented to implicitly enable the certificate policy
    check when doing certificate verification. However the implementation of the function does not enable the
    check which allows certificates with invalid or incorrect policies to pass the certificate verification.
    As suddenly enabling the policy check could break existing deployments it was decided to keep the existing
    behavior of the X509_VERIFY_PARAM_add0_policy() function. Instead the applications that require OpenSSL to
    perform certificate policy check need to use X509_VERIFY_PARAM_set1_policies() or explicitly enable the
    policy check by calling X509_VERIFY_PARAM_set_flags() with the X509_V_FLAG_POLICY_CHECK flag argument.
    Certificate policy checks are disabled by default in OpenSSL and are not commonly used by applications.
    (CVE-2023-0466)

  - Issue summary: Processing some specially crafted ASN.1 object identifiers or data containing them may be
    very slow. Impact summary: Applications that use OBJ_obj2txt() directly, or use any of the OpenSSL
    subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message size limit may experience notable to
    very long delays when processing those messages, which may lead to a Denial of Service. An OBJECT
    IDENTIFIER is composed of a series of numbers - sub-identifiers - most of which have no size limit.
    OBJ_obj2txt() may be used to translate an ASN.1 OBJECT IDENTIFIER given in DER encoding form (using the
    OpenSSL type ASN1_OBJECT) to its canonical numeric text form, which are the sub-identifiers of the OBJECT
    IDENTIFIER in decimal form, separated by periods. When one of the sub-identifiers in the OBJECT IDENTIFIER
    is very large (these are sizes that are seen as absurdly large, taking up tens or hundreds of KiBs), the
    translation to a decimal number in text may take a very long time. The time complexity is O(n^2) with 'n'
    being the size of the sub-identifiers in bytes (*). With OpenSSL 3.0, support to fetch cryptographic
    algorithms using names / identifiers in string form was introduced. This includes using OBJECT IDENTIFIERs
    in canonical numeric text form as identifiers for fetching algorithms. Such OBJECT IDENTIFIERs may be
    received through the ASN.1 structure AlgorithmIdentifier, which is commonly used in multiple protocols to
    specify what cryptographic algorithm should be used to sign or verify, encrypt or decrypt, or digest
    passed data. Applications that call OBJ_obj2txt() directly with untrusted data are affected, with any
    version of OpenSSL. If the use is for the mere purpose of display, the severity is considered low. In
    OpenSSL 3.0 and newer, this affects the subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS. It also impacts
    anything that processes X.509 certificates, including simple things like verifying its signature. The
    impact on TLS is relatively low, because all versions of OpenSSL have a 100KiB limit on the peer's
    certificate chain. Additionally, this only impacts clients, or servers that have explicitly enabled client
    authentication. In OpenSSL 1.1.1 and 1.0.2, this only affects displaying diverse objects, such as X.509
    certificates. This is assumed to not happen in such a way that it would cause a Denial of Service, so
    these versions are considered not affected by this issue in such a way that it would be cause for concern,
    and the severity is therefore considered low. (CVE-2023-2650)

Note that Nessus has not tested for these issues 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-2023-1762.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-0464.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-0465.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-0466.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-2650.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update openssl' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/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:N/I:L/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-2023-0466");

  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:"2023/03/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/06/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/06/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssl-static");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023 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("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_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);

var pkgs = [
    {'reference':'openssl-1.0.2k-16.163.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-1.0.2k-16.163.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-debuginfo-1.0.2k-16.163.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-debuginfo-1.0.2k-16.163.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-devel-1.0.2k-16.163.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-devel-1.0.2k-16.163.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-perl-1.0.2k-16.163.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-perl-1.0.2k-16.163.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-static-1.0.2k-16.163.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssl-static-1.0.2k-16.163.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = 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['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 (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    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 (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openssl / openssl-debuginfo / openssl-devel / etc");
}