Oracle Linux 7 : Unbreakable Enterprise kernel-container (ELSA-2021-9453)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2021-9453.
##

include('compat.inc');

if (description)
{
  script_id(180951);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/09/07");

  script_cve_id(
    "CVE-2020-24586",
    "CVE-2020-24587",
    "CVE-2020-24588",
    "CVE-2020-26147",
    "CVE-2021-3609",
    "CVE-2021-3612",
    "CVE-2021-3653",
    "CVE-2021-3656",
    "CVE-2021-22543",
    "CVE-2021-23134",
    "CVE-2021-34693"
  );

  script_name(english:"Oracle Linux 7 : Unbreakable Enterprise kernel-container (ELSA-2021-9453)");

  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 7 host has a package installed that is affected by multiple vulnerabilities as referenced in the
ELSA-2021-9453 advisory.

  - A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when
    processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested
    guest (L2). Due to improper validation of the int_ctl field, this issue could allow a malicious L1 to
    enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest
    would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak
    of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to
    5.14-rc7. (CVE-2021-3653)

  - net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from
    kernel stack memory because parts of a data structure are uninitialized. (CVE-2021-34693)

  - An out-of-bounds memory write flaw was found in the Linux kernel's joystick devices subsystem in versions
    before 5.9-rc1, in the way the user calls ioctl JSIOCSBTNMAP. This flaw allows a local user to crash the
    system or possibly escalate their privileges on the system. The highest threat from this vulnerability is
    to confidentiality, integrity, as well as system availability. (CVE-2021-3612)

  - The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent
    Privacy (WEP) doesn't require that received fragments be cleared from memory after (re)connecting to a
    network. Under the right circumstances, when another device sends fragmented frames encrypted using WEP,
    CCMP, or GCMP, this can be abused to inject arbitrary network packets and/or exfiltrate user data.
    (CVE-2020-24586)

  - Use After Free vulnerability in nfc sockets in the Linux Kernel before 5.12.4 allows local attackers to
    elevate their privileges. In typical configurations, the issue can only be triggered by a privileged local
    user with the CAP_NET_RAW capability. (CVE-2021-23134)

  - The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent
    Privacy (WEP) doesn't require that all fragments of a frame are encrypted under the same key. An adversary
    can abuse this to decrypt selected fragments when another device sends fragmented frames and the WEP,
    CCMP, or GCMP encryption key is periodically renewed. (CVE-2020-24587)

  - The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent
    Privacy (WEP) doesn't require that the A-MSDU flag in the plaintext QoS header field is authenticated.
    Against devices that support receiving non-SSP A-MSDU frames (which is mandatory as part of 802.11n), an
    adversary can abuse this to inject arbitrary network packets. (CVE-2020-24588)

  - An issue was discovered in the Linux kernel 5.8.9. The WEP, WPA, WPA2, and WPA3 implementations reassemble
    fragments even though some of them were sent in plaintext. This vulnerability can be abused to inject
    packets and/or exfiltrate selected fragments when another device sends fragmented frames and the WEP,
    CCMP, or GCMP data-confidentiality protocol is used. (CVE-2020-26147)

  - .A flaw was found in the CAN BCM networking protocol in the Linux kernel, where a local attacker can abuse
    a flaw in the CAN subsystem to corrupt memory, crash the system or escalate privileges. This race
    condition in net/can/bcm.c in the Linux kernel allows for local privilege escalation to root.
    (CVE-2021-3609)

  - An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass
    RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users
    with the ability to start and control a VM to read/write random pages of memory and can result in local
    privilege escalation. (CVE-2021-22543)

  - A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when
    processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested
    guest (L2). Due to improper validation of the virt_ext field, this issue could allow a malicious L1 to
    disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the
    L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire
    system, leak of sensitive data or potential guest-to-host escape. (CVE-2021-3656)

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://linux.oracle.com/errata/ELSA-2021-9453.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel-uek-container package.");
  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:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3656");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/05/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/09/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/09/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-container");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle 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("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  exit(0);
}


include('ksplice.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');
var os_release = get_kb_item("Host/RedHat/release");
if (isnull(os_release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 7', 'Oracle Linux ' + 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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);
if ('x86_64' >!< cpu) audit(AUDIT_ARCH_NOT, 'x86_64', cpu);

var machine_uptrack_level = get_one_kb_item('Host/uptrack-uname-r');
if (machine_uptrack_level)
{
  var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
  var fixed_uptrack_levels = ['4.14.35-2047.507.7.4.el7'];
  foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
    if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
    {
      audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ELSA-2021-9453');
    }
  }
  __rpm_report = 'Running KSplice level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}

var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '4.14';
if (kernel_major_minor != expected_kernel_major_minor)
  audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);

var pkgs = [
    {'reference':'kernel-uek-container-4.14.35-2047.507.7.4.el7', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-container-4.14.35'}
];

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 = '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 (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (reference && _release) {
    if (exists_check) {
        if (rpm_exists(release:_release, rpm:exists_check) && 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++;
    } else {
        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_HOLE,
      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, 'kernel-uek-container');
}