Amazon Linux AMI : kernel (ALAS-2023-1827)

2023-09-2500:00:00

www.tenable.com

amazon linux ami

kernel

vulnerabilities

use-after-free

buffer overrun

denial of service

alas-2023-1827 advisory

privilege escalation

deadlock

netfilter

netback driver

cls_route

cls_u32

sctp subsystem

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

AI Score

Confidence

High

EPSS

0.001

Percentile

25.6%

JSON

The version of kernel installed on the remote host is prior to 4.14.322-170.535. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2023-1827 advisory.

A use-after-free vulnerability was found in the Linux kernel’s netfilter subsystem in net/netfilter/nf_tables_api.c. Mishandled error handling with NFT_MSG_NEWRULE makes it possible to use a dangling pointer in the same transaction causing a use-after-free vulnerability. This flaw allows a local attacker with user access to cause a privilege escalation issue. We recommend upgrading past commit 1240eb93f0616b21c675416516ff3d74798fdc97. (CVE-2023-3390)
The fix for XSA-423 added logic to Linux’es netback driver to deal with a frontend splitting a packet in a way such that not all of the headers would come in one piece. Unfortunately the logic introduced there didn’t account for the extreme case of the entire packet being split into as many pieces as permitted by the protocol, yet still being smaller than the area that’s specially dealt with to keep all (possible) headers together. Such an unusual packet would therefore trigger a buffer overrun in the driver.
(CVE-2023-34319)
A use-after-free vulnerability in the Linux kernel’s net/sched: cls_route component can be exploited to achieve local privilege escalation. When route4_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8.
(CVE-2023-4206)
A use-after-free vulnerability in the Linux kernel’s net/sched: cls_u32 component can be exploited to achieve local privilege escalation. When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
(CVE-2023-4208)
A denial of service vulnerability due to a deadlock was found in sctp_auto_asconf_init in net/sctp/socket.c in the Linux kernel’s SCTP subsystem. This flaw allows guests with local user privileges to trigger a deadlock and potentially crash the system. (CVE-2024-0639)

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 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2023-1827.
##

include('compat.inc');

if (description)
{
  script_id(181850);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/06");

  script_cve_id(
    "CVE-2023-3390",
    "CVE-2023-34319",
    "CVE-2023-4128",
    "CVE-2023-4206",
    "CVE-2023-4208",
    "CVE-2024-0639"
  );

  script_name(english:"Amazon Linux AMI : kernel (ALAS-2023-1827)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of kernel installed on the remote host is prior to 4.14.322-170.535. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS-2023-1827 advisory.

  - A use-after-free vulnerability was found in the Linux kernel's netfilter subsystem in
    net/netfilter/nf_tables_api.c. Mishandled error handling with NFT_MSG_NEWRULE makes it possible to use a
    dangling pointer in the same transaction causing a use-after-free vulnerability. This flaw allows a local
    attacker with user access to cause a privilege escalation issue. We recommend upgrading past commit
    1240eb93f0616b21c675416516ff3d74798fdc97. (CVE-2023-3390)

  - The fix for XSA-423 added logic to Linux'es netback driver to deal with a frontend splitting a packet in a
    way such that not all of the headers would come in one piece. Unfortunately the logic introduced there
    didn't account for the extreme case of the entire packet being split into as many pieces as permitted by
    the protocol, yet still being smaller than the area that's specially dealt with to keep all (possible)
    headers together. Such an unusual packet would therefore trigger a buffer overrun in the driver.
    (CVE-2023-34319)

  - A use-after-free vulnerability in the Linux kernel's net/sched: cls_route component can be exploited to
    achieve local privilege escalation. When route4_change() is called on an existing filter, the whole
    tcf_result struct is always copied into the new instance of the filter. This causes a problem when
    updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the
    success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading
    to a use-after-free. We recommend upgrading past commit b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8.
    (CVE-2023-4206)

  - A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to
    achieve local privilege escalation. When u32_change() is called on an existing filter, the whole
    tcf_result struct is always copied into the new instance of the filter. This causes a problem when
    updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the
    success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading
    to a use-after-free. We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
    (CVE-2023-4208)

  - A denial of service vulnerability due to a deadlock was found in sctp_auto_asconf_init in
    net/sctp/socket.c in the Linux kernel's SCTP subsystem. This flaw allows guests with local user privileges
    to trigger a deadlock and potentially crash the system. (CVE-2024-0639)

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://alas.aws.amazon.com/ALAS-2023-1827.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-3390.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-34319.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-4128.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-4206.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2023-4208.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2024-0639.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update kernel' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/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:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-4208");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/06/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/09/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/09/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-i686");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "kpatch.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}

include("rpm.inc");
include("hotfixes.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

if (get_one_kb_item("Host/kpatch/kernel-cves"))
{
  set_hotfix_type("kpatch");
  var cve_list = make_list("CVE-2023-3390", "CVE-2023-4128", "CVE-2023-4206", "CVE-2023-4208", "CVE-2023-34319", "CVE-2024-0639");
  if (hotfix_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, "kpatch hotfix for ALAS-2023-1827");
  }
  else
  {
    __rpm_report = hotfix_reporting_text();
  }
}
var pkgs = [
    {'reference':'kernel-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-common-i686-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-common-x86_64-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-headers-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-debuginfo-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-debuginfo-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-devel-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-devel-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-debuginfo-4.14.322-170.535.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'perf-debuginfo-4.14.322-170.535.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];

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 = 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 && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    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_WARNING,
      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 / kernel-debuginfo / kernel-debuginfo-common-x86_64 / etc");
}