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nessusUbuntu Security Notice (C) 2021-2024 Canonical, Inc. / NASL script (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.UBUNTU_USN-5073-1.NASL
HistorySep 09, 2021 - 12:00 a.m.

Ubuntu 16.04 ESM / 18.04 LTS : Linux kernel vulnerabilities (USN-5073-1)

2021-09-0900:00:00
Ubuntu Security Notice (C) 2021-2024 Canonical, Inc. / NASL script (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
28

7.2 High

CVSS2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

8.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

8.2 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

23.5%

The remote Ubuntu 16.04 ESM / 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-5073-1 advisory.

  • 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)

  • 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)

  • 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)

  • In drivers/char/virtio_console.c in the Linux kernel before 5.13.4, data corruption or loss can be triggered by an untrusted device that supplies a buf->len value exceeding the buffer size. NOTE: the vendor indicates that the cited data corruption is not a vulnerability in any existing use case; the length validation was added solely for robustness in the face of anomalous host OS behavior (CVE-2021-38160)

Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5073-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

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

if (description)
{
  script_id(153177);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2021-3612",
    "CVE-2021-3653",
    "CVE-2021-3656",
    "CVE-2021-34693",
    "CVE-2021-38160"
  );
  script_xref(name:"USN", value:"5073-1");

  script_name(english:"Ubuntu 16.04 ESM / 18.04 LTS : Linux kernel vulnerabilities (USN-5073-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 ESM / 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as
referenced in the USN-5073-1 advisory.

  - 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)

  - 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)

  - 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)

  - In drivers/char/virtio_console.c in the Linux kernel before 5.13.4, data corruption or loss can be
    triggered by an untrusted device that supplies a buf->len value exceeding the buffer size. NOTE: the
    vendor indicates that the cited data corruption is not a vulnerability in any existing use case; the
    length validation was added solely for robustness in the face of anomalous host OS behavior
    (CVE-2021-38160)

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://ubuntu.com/security/notices/USN-5073-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel 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:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-38160");
  script_set_attribute(attribute:"cvss3_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:"2021/06/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/09/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/09/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:esm");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1027-dell300x");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1080-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1099-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1111-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1112-snapdragon");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1123-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-156-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-156-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-156-lowlatency");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2021-2024 Canonical, Inc. / NASL script (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "linux_alt_patch_detect.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');
include('ksplice.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('16.04' >< os_release || '18.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var kernel_mappings = {
  '16.04': {
    '4.15.0': {
      'generic': '4.15.0-156',
      'lowlatency': '4.15.0-156',
      'oracle': '4.15.0-1080',
      'aws': '4.15.0-1111',
      'azure': '4.15.0-1123'
    }
  },
  '18.04': {
    '4.15.0': {
      'generic': '4.15.0-156',
      'generic-lpae': '4.15.0-156',
      'lowlatency': '4.15.0-156',
      'dell300x': '4.15.0-1027',
      'oracle': '4.15.0-1080',
      'kvm': '4.15.0-1099',
      'aws': '4.15.0-1111',
      'snapdragon': '4.15.0-1112',
      'azure': '4.15.0-1123'
    }
  }
};

var host_kernel_release = get_kb_item('Host/uptrack-uname-r');
if (empty_or_null(host_kernel_release)) host_kernel_release = get_kb_item_or_exit('Host/uname-r');
var host_kernel_base_version = get_kb_item_or_exit('Host/Debian/kernel-base-version');
var host_kernel_type = get_kb_item_or_exit('Host/Debian/kernel-type');
if(empty_or_null(kernel_mappings[os_release][host_kernel_base_version][host_kernel_type])) audit(AUDIT_INST_VER_NOT_VULN, 'kernel ' + host_kernel_release);

var extra = '';
var kernel_fixed_version = kernel_mappings[os_release][host_kernel_base_version][host_kernel_type] + "-" + host_kernel_type;
if (deb_ver_cmp(ver1:host_kernel_release, ver2:kernel_fixed_version) < 0)
{
  extra = extra + 'Running Kernel level of ' + host_kernel_release + ' does not meet the minimum fixed level of ' + kernel_fixed_version + ' for this advisory.\n\n';
}
  else
{
  audit(AUDIT_PATCH_INSTALLED, 'Kernel package for USN-5073-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2021-3612', 'CVE-2021-3653', 'CVE-2021-3656', 'CVE-2021-34693', 'CVE-2021-38160');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-5073-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
VendorProductVersionCPE
canonicalubuntu_linux16.04cpe:/o:canonical:ubuntu_linux:16.04:-:esm
canonicalubuntu_linux18.04cpe:/o:canonical:ubuntu_linux:18.04:-:lts
canonicalubuntu_linuxlinux-image-4.15.0-1027-dell300xp-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1027-dell300x
canonicalubuntu_linuxlinux-image-4.15.0-1080-oraclep-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1080-oracle
canonicalubuntu_linuxlinux-image-4.15.0-1099-kvmp-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1099-kvm
canonicalubuntu_linuxlinux-image-4.15.0-1111-awsp-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1111-aws
canonicalubuntu_linuxlinux-image-4.15.0-1112-snapdragonp-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1112-snapdragon
canonicalubuntu_linuxlinux-image-4.15.0-1123-azurep-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1123-azure
canonicalubuntu_linuxlinux-image-4.15.0-156-genericp-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-156-generic
canonicalubuntu_linuxlinux-image-4.15.0-156-generic-lpaep-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-156-generic-lpae
Rows per page:
1-10 of 111

7.2 High

CVSS2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

COMPLETE

Integrity Impact

COMPLETE

Availability Impact

COMPLETE

AV:L/AC:L/Au:N/C:C/I:C/A:C

8.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

8.2 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

23.5%