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This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.ORACLELINUX_ELSA-2020-5848.NASL
HistorySep 15, 2020 - 12:00 a.m.

Oracle Linux 7 / 8 : Unbreakable Enterprise kernel (ELSA-2020-5848)

2020-09-1500:00:00
This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
63

7 High

AI Score

Confidence

High

The remote Oracle Linux 7 / 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2020-5848 advisory.

  • A flaw was found in the Linux kernels implementation of the invert video code on VGA consoles when a local attacker attempts to resize the console, calling an ioctl VT_RESIZE, which causes an out-of-bounds write to occur. This flaw allows a local user with access to the VGA console to crash the system, potentially escalating their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2020-14331)

  • In the Linux kernel before 5.7.8, fs/nfsd/vfs.c (in the NFS server) can set incorrect permissions on new filesystem objects when the filesystem lacks ACL support, aka CID-22cf8419f131. This occurs because the current umask is not considered. (CVE-2020-24394)

  • A flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the creation of that ZRAM device. With this vulnerability, continually reading the device may consume a large amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random userspace processes, possibly making the system inoperable. (CVE-2020-10781)

  • The Linux kernel through 5.7.11 allows remote attackers to make observations that help to obtain sensitive information about the internal state of the network RNG, aka CID-f227e3ec3b5c. This is related to drivers/char/random.c and kernel/time/timer.c. (CVE-2020-16166)

  • A flaw was found in the Linux kernels SELinux LSM hook implementation before version 5.7, where it incorrectly assumed that an skb would only contain a single netlink message. The hook would incorrectly only validate the first netlink message in the skb and allow or deny the rest of the messages within the skb with the granted permission without further processing. (CVE-2020-10751)

  • An issue was discovered in the Linux kernel through 5.6.11. btree_gc_coalesce in drivers/md/bcache/btree.c has a deadlock if a coalescing operation fails. (CVE-2020-12771)

Note that Nessus has not tested for this issue 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 Oracle Linux Security Advisory ELSA-2020-5848.
##

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

if (description)
{
  script_id(140588);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/20");

  script_cve_id(
    "CVE-2020-10751",
    "CVE-2020-10781",
    "CVE-2020-12771",
    "CVE-2020-14331",
    "CVE-2020-16166",
    "CVE-2020-24394"
  );

  script_name(english:"Oracle Linux 7 / 8 : Unbreakable Enterprise kernel (ELSA-2020-5848)");

  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 / 8 host has packages installed that are affected by multiple vulnerabilities as referenced in
the ELSA-2020-5848 advisory.

  - A flaw was found in the Linux kernels implementation of the invert video code on VGA consoles when a
    local attacker attempts to resize the console, calling an ioctl VT_RESIZE, which causes an out-of-bounds
    write to occur. This flaw allows a local user with access to the VGA console to crash the system,
    potentially escalating their privileges on the system. The highest threat from this vulnerability is to
    data confidentiality and integrity as well as system availability. (CVE-2020-14331)

  - In the Linux kernel before 5.7.8, fs/nfsd/vfs.c (in the NFS server) can set incorrect permissions on new
    filesystem objects when the filesystem lacks ACL support, aka CID-22cf8419f131. This occurs because the
    current umask is not considered. (CVE-2020-24394)

  - A flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local
    account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in
    the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the
    creation of that ZRAM device. With this vulnerability, continually reading the device may consume a large
    amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random
    userspace processes, possibly making the system inoperable. (CVE-2020-10781)

  - The Linux kernel through 5.7.11 allows remote attackers to make observations that help to obtain sensitive
    information about the internal state of the network RNG, aka CID-f227e3ec3b5c. This is related to
    drivers/char/random.c and kernel/time/timer.c. (CVE-2020-16166)

  - A flaw was found in the Linux kernels SELinux LSM hook implementation before version 5.7, where it
    incorrectly assumed that an skb would only contain a single netlink message. The hook would incorrectly
    only validate the first netlink message in the skb and allow or deny the rest of the messages within the
    skb with the granted permission without further processing. (CVE-2020-10751)

  - An issue was discovered in the Linux kernel through 5.6.11. btree_gc_coalesce in drivers/md/bcache/btree.c
    has a deadlock if a coalescing operation fails. (CVE-2020-12771)

Note that Nessus has not tested for this issue 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-2020-5848.html");
  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: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:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-14331");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2020-24394");

  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:"2020/05/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/09/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/09/15");

  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:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-tools-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:python-perf");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2020-2024 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('audit.inc');
include('global_settings.inc');
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 release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
var os_ver = os_ver[1];
if (! preg(pattern:"^(7|8)([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 7 / 8', '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);

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 = ['5.4.17-2011.6.2.el7uek', '5.4.17-2011.6.2.el8uek'];
  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-2020-5848');
    }
  }
  __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 = '5.4';
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-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
    {'reference':'kernel-uek-5.4.17-2011.6.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
    {'reference':'kernel-uek-debug-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
    {'reference':'kernel-uek-debug-5.4.17-2011.6.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
    {'reference':'kernel-uek-debug-devel-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
    {'reference':'kernel-uek-debug-devel-5.4.17-2011.6.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
    {'reference':'kernel-uek-devel-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
    {'reference':'kernel-uek-devel-5.4.17-2011.6.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
    {'reference':'kernel-uek-doc-5.4.17-2011.6.2.el7uek', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-5.4.17'},
    {'reference':'kernel-uek-tools-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-5.4.17'},
    {'reference':'kernel-uek-tools-5.4.17-2011.6.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-5.4.17'},
    {'reference':'kernel-uek-tools-libs-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-tools-libs-5.4.17'},
    {'reference':'perf-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python-perf-5.4.17-2011.6.2.el7uek', 'cpu':'aarch64', 'release':'7', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-uek-5.4.17-2011.6.2.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
    {'reference':'kernel-uek-5.4.17-2011.6.2.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
    {'reference':'kernel-uek-debug-5.4.17-2011.6.2.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
    {'reference':'kernel-uek-debug-5.4.17-2011.6.2.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
    {'reference':'kernel-uek-debug-devel-5.4.17-2011.6.2.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
    {'reference':'kernel-uek-debug-devel-5.4.17-2011.6.2.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
    {'reference':'kernel-uek-devel-5.4.17-2011.6.2.el8uek', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
    {'reference':'kernel-uek-devel-5.4.17-2011.6.2.el8uek', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
    {'reference':'kernel-uek-doc-5.4.17-2011.6.2.el8uek', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-5.4.17'}
];

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 / kernel-uek-debug / kernel-uek-debug-devel / etc');
}
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AI Score

Confidence

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