Ubuntu 21.04 : Linux kernel vulnerabilities (USN-4950-1)

#%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-4950-1. 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(149406);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/08/27");

  script_cve_id("CVE-2021-3489", "CVE-2021-3490", "CVE-2021-3491");
  script_xref(name:"USN", value:"4950-1");

  script_name(english:"Ubuntu 21.04 : Linux kernel vulnerabilities (USN-4950-1)");

  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 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the
USN-4950-1 advisory.

    Ryota Shiga discovered that the eBPF implementation in the Linux kernel did not properly verify that a BPF
    program only reserved as much memory for a ring buffer as was allocated. A local attacker could use this
    to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-3489)

    Manfred Paul discovered that the eBPF implementation in the Linux kernel did not properly track bounds on
    bitwise operations. A local attacker could use this to cause a denial of service (system crash) or execute
    arbitrary code. (CVE-2021-3490)

    Billy Jheng Bing-Jhong discovered that the io_uring implementation of the Linux kernel did not properly
    enforce the MAX_RW_COUNT limit in some situations. A local attacker could use this to cause a denial of
    service (system crash) or execute arbitrary code. (CVE-2021-3491)

    Norbert Slusarek discovered that the CAN ISOTP protocol implementation in the Linux kernel contained a
    race condition. A local attacker could use this to cause a denial of service (system crash) or possibly
    execute arbitrary code. Please note that to address this issue, SF_BROADCAST support was removed
    temporarily from the CAN ISOTP implementation in Ubuntu 21.04 kernels. (LP: #1927409)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

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-4950-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  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:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3491");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_core", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Linux eBPF ALU32 32-bit Invalid Bounds Tracking LPE');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/05/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/05/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/05/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:21.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1005-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1006-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1007-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1007-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1007-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1008-raspi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1008-raspi-nolpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-17-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-17-generic-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-17-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-17-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k-hwe-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-64k-hwe-20.04-edge");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-hwe-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-hwe-20.04-edge");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-hwe-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-hwe-20.04-edge");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-gke");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-kvm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-hwe-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-hwe-20.04-edge");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-oem-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi-nolpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-hwe-20.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-hwe-20.04-edge");
  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");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.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 (! ('21.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 21.04', '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 pkgs = [
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1005-azure', 'pkgver': '5.11.0-1005.5'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1006-oracle', 'pkgver': '5.11.0-1006.6'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1007-aws', 'pkgver': '5.11.0-1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1007-gcp', 'pkgver': '5.11.0-1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1007-kvm', 'pkgver': '5.11.0-1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1008-raspi', 'pkgver': '5.11.0-1008.8'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-1008-raspi-nolpae', 'pkgver': '5.11.0-1008.8'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-17-generic', 'pkgver': '5.11.0-17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-17-generic-64k', 'pkgver': '5.11.0-17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-17-generic-lpae', 'pkgver': '5.11.0-17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-5.11.0-17-lowlatency', 'pkgver': '5.11.0-17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-aws', 'pkgver': '5.11.0.1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-azure', 'pkgver': '5.11.0.1005.5'},
    {'osver': '21.04', 'pkgname': 'linux-image-gcp', 'pkgver': '5.11.0.1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-64k', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-64k-hwe-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-64k-hwe-20.04-edge', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-hwe-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-hwe-20.04-edge', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-lpae', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-lpae-hwe-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-generic-lpae-hwe-20.04-edge', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-gke', 'pkgver': '5.11.0.1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-kvm', 'pkgver': '5.11.0.1007.7'},
    {'osver': '21.04', 'pkgname': 'linux-image-lowlatency', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-lowlatency-hwe-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-lowlatency-hwe-20.04-edge', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-oem-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-oracle', 'pkgver': '5.11.0.1006.6'},
    {'osver': '21.04', 'pkgname': 'linux-image-raspi', 'pkgver': '5.11.0.1008.6'},
    {'osver': '21.04', 'pkgname': 'linux-image-raspi-nolpae', 'pkgver': '5.11.0.1008.6'},
    {'osver': '21.04', 'pkgname': 'linux-image-virtual', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-virtual-hwe-20.04', 'pkgver': '5.11.0.17.18'},
    {'osver': '21.04', 'pkgname': 'linux-image-virtual-hwe-20.04-edge', 'pkgver': '5.11.0.17.18'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'linux-image-5.11.0-1005-azure / linux-image-5.11.0-1006-oracle / etc');
}