RHEL 6 : rpm (Unpatched Vulnerability)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory rpm. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(195653);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/05/11");

  script_cve_id(
    "CVE-2017-7500",
    "CVE-2017-7501",
    "CVE-2021-3421",
    "CVE-2021-3521",
    "CVE-2021-20248",
    "CVE-2021-20266",
    "CVE-2021-20271",
    "CVE-2021-35937",
    "CVE-2021-35938",
    "CVE-2021-35939"
  );

  script_name(english:"RHEL 6 : rpm (Unpatched Vulnerability)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat 6 host is affected by multiple vulnerabilities that will not be patched.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 6 host has one or more packages installed that are affected by multiple
vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - rpm: Following symlinks to directories when installing packages allows privilege escalation
    (CVE-2017-7500)

  - rpm: Following symlinks to files when installing packages allows privilege escalation (CVE-2017-7501)

  - Rejected reason: DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn
    by its CNA. Further investigation showed that it was not a security issue. Notes: none. (CVE-2021-20248)

  - A flaw was found in RPM's hdrblobInit() in lib/header.c. This flaw allows an attacker who can modify the
    rpmdb to cause an out-of-bounds read. The highest threat from this vulnerability is to system
    availability. (CVE-2021-20266)

  - 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)

  - There is a flaw in RPM's signature functionality. OpenPGP subkeys are associated with a primary key via a
    binding signature. RPM does not check the binding signature of subkeys prior to importing them. If an
    attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate
    public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data
    integrity. To exploit this flaw, an attacker must either compromise an RPM repository or convince an
    administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and
    public keys from trusted sources. (CVE-2021-3521)

  - A race condition vulnerability was found in rpm. A local unprivileged user could use this flaw to bypass
    the checks that were introduced in response to CVE-2017-7500 and CVE-2017-7501, potentially gaining root
    privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as
    system availability. (CVE-2021-35937)

  - A symbolic link issue was found in rpm. It occurs when rpm sets the desired permissions and credentials
    after installing a file. A local unprivileged user could use this flaw to exchange the original file with
    a symbolic link to a security-critical file and escalate their privileges on the system. The highest
    threat from this vulnerability is to data confidentiality and integrity as well as system availability.
    (CVE-2021-35938)

  - It was found that the fix for CVE-2017-7500 and CVE-2017-7501 was incomplete: the check was only
    implemented for the parent directory of the file to be created. A local unprivileged user who owns another
    ancestor directory could potentially use this flaw to gain root privileges. The highest threat from this
    vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2021-35939)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package
is installed.");
  script_set_attribute(attribute:"solution", value:
"The vendor has acknowledged the vulnerabilities but no solution has been provided. Refer to the vendor for remediation
guidance.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-7500");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2017-7501");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/10/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/05/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:6");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:rpm");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Red Hat Local Security Checks");

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

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

  exit(0);
}


include('rpm.inc');
include('rhel.inc');

if (!get_kb_item("global_settings/vendor_unpatched"))
exit(0, "Unpatched Vulnerabilities Detection not active.");

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Red Hat' >!< os_release) audit(AUDIT_OS_NOT, 'Red Hat');
var os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
os_ver = os_ver[1];
if (!rhel_check_release(operator: 'ge', os_version: os_ver, rhel_version: '6')) audit(AUDIT_OS_NOT, 'Red Hat 6.x', 'Red Hat ' + os_ver);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'pkgs': [
      {'reference':'rpm', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'unpatched_pkg':'rpm'}
    ]
  }
];


var flag = 0;
foreach var constraint_array ( constraints ) {
  var repo_relative_urls = NULL;
  var enterprise_linux_flag = rhel_repo_urls_has_content_dist_rhel(repo_urls:repo_relative_urls);
  foreach var pkg ( constraint_array['pkgs'] ) {
    var unpatched_pkg = NULL;
    var _release = NULL;
    var sp = NULL;
    var el_string = NULL;
    var rpm_spec_vers_cmp = NULL;
    var exists_check = NULL;
    var cves = NULL;
    if (!empty_or_null(pkg['unpatched_pkg'])) unpatched_pkg = pkg['unpatched_pkg'];
    if (!empty_or_null(pkg['release'])) _release = 'RHEL' + pkg['release'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (unpatched_pkg &&
        _release &&
        (!exists_check || rpm_exists(release:_release, rpm:exists_check)) &&
        unpatched_package_exists(release:_release, package:unpatched_pkg, cves: cves)) flag++;
  }
}

if (flag)
{
  var extra = NULL;
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : unpatched_packages_report()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'rpm');
}