Ubuntu 20.04 LTS / 22.04 LTS : Linux kernel vulnerabilities (USN-6446-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-6446-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(183454);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/09");

  script_cve_id(
    "CVE-2023-4244",
    "CVE-2023-4622",
    "CVE-2023-4623",
    "CVE-2023-4881",
    "CVE-2023-4921",
    "CVE-2023-5197",
    "CVE-2023-34319",
    "CVE-2023-42752",
    "CVE-2023-42753",
    "CVE-2023-42755",
    "CVE-2023-42756"
  );
  script_xref(name:"USN", value:"6446-1");

  script_name(english:"Ubuntu 20.04 LTS / 22.04 LTS : Linux kernel vulnerabilities (USN-6446-1)");

  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 20.04 LTS / 22.04 LTS host has a package installed that is affected by multiple vulnerabilities as
referenced in the USN-6446-1 advisory.

  - 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 netfilter: nf_tables component can be exploited to
    achieve local privilege escalation. Due to a race condition between nf_tables netlink control plane
    transaction and nft_set element garbage collection, it is possible to underflow the reference counter
    causing a use-after-free vulnerability. We recommend upgrading past commit
    3e91b0ebd994635df2346353322ac51ce84ce6d8. (CVE-2023-4244)

  - An integer overflow flaw was found in the Linux kernel. This issue leads to the kernel allocating
    `skb_shared_info` in the userspace, which is exploitable in systems without SMAP protection since
    `skb_shared_info` contains references to function pointers. (CVE-2023-42752)

  - An array indexing vulnerability was found in the netfilter subsystem of the Linux kernel. A missing macro
    could lead to a miscalculation of the `h->nets` array offset, providing attackers with the primitive to
    arbitrarily increment/decrement a memory buffer out-of-bound. This issue may allow a local user to crash
    the system or potentially escalate their privileges on the system. (CVE-2023-42753)

  - A flaw was found in the IPv4 Resource Reservation Protocol (RSVP) classifier in the Linux kernel. The xprt
    pointer may go beyond the linear part of the skb, leading to an out-of-bounds read in the `rsvp_classify`
    function. This issue may allow a local user to crash the system and cause a denial of service.
    (CVE-2023-42755)

  - A flaw was found in the Netfilter subsystem of the Linux kernel. A race condition between IPSET_CMD_ADD
    and IPSET_CMD_SWAP can lead to a kernel panic due to the invocation of `__ip_set_put` on a wrong `set`.
    This issue may allow a local user to crash the system. (CVE-2023-42756)

  - A use-after-free vulnerability in the Linux kernel's af_unix component can be exploited to achieve local
    privilege escalation. The unix_stream_sendpage() function tries to add data to the last skb in the peer's
    recv queue without locking the queue. Thus there is a race where unix_stream_sendpage() could access an
    skb locklessly that is being released by garbage collection, resulting in use-after-free. We recommend
    upgrading past commit 790c2f9d15b594350ae9bca7b236f2b1859de02c. (CVE-2023-4622)

  - A use-after-free vulnerability in the Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control)
    component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve
    (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call
    vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling
    pointer that can cause a use-after-free. We recommend upgrading past commit
    b3d26c5702c7d6c45456326e56d2ccf3f103e60f. (CVE-2023-4623)

  - Rejected reason: CVE-2023-4881 was wrongly assigned to a bug that was deemed to be a non-security issue by
    the Linux kernel security team. (CVE-2023-4881)

  - A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to
    achieve local privilege escalation. When the plug qdisc is used as a class of the qfq qdisc, sending
    network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug
    and lack of error checking in agg_dequeue(). We recommend upgrading past commit
    8fc134fee27f2263988ae38920bc03da416b03d8. (CVE-2023-4921)

  - A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to
    achieve local privilege escalation. Addition and removal of rules from chain bindings within the same
    transaction causes leads to use-after-free. We recommend upgrading past commit
    f15f29fd4779be8a418b66e9d52979bb6d6c2325. (CVE-2023-5197)

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-6446-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  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: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:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-4921");

  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:"2023/08/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/10/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/10/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1031-gkeop");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1039-nvidia");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1039-nvidia-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1041-ibm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1041-raspi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1045-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1046-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1048-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1050-azure-fde");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-87-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-87-generic-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-87-generic-lpae");
  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) 2023-2024 Canonical, Inc. / NASL script (C) 2023-2024 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 (! ('20.04' >< os_release || '22.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04 / 22.04', '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 = {
  '20.04': {
    '5.15.0': {
      'generic': '5.15.0-87',
      'generic-64k': '5.15.0-87',
      'generic-lpae': '5.15.0-87',
      'ibm': '5.15.0-1041',
      'aws': '5.15.0-1048',
      'azure-fde': '5.15.0-1050'
    }
  },
  '22.04': {
    '5.15.0': {
      'generic': '5.15.0-87',
      'generic-64k': '5.15.0-87',
      'generic-lpae': '5.15.0-87',
      'gkeop': '5.15.0-1031',
      'nvidia': '5.15.0-1039',
      'nvidia-lowlatency': '5.15.0-1039',
      'ibm': '5.15.0-1041',
      'raspi': '5.15.0-1041',
      'gcp': '5.15.0-1045',
      'oracle': '5.15.0-1046',
      'aws': '5.15.0-1048',
      'azure-fde': '5.15.0-1050'
    }
  }
};

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-6446-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2023-4244', 'CVE-2023-4622', 'CVE-2023-4623', 'CVE-2023-4881', 'CVE-2023-4921', 'CVE-2023-5197', 'CVE-2023-34319', 'CVE-2023-42752', 'CVE-2023-42753', 'CVE-2023-42755', 'CVE-2023-42756');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-6446-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : extra
  );
  exit(0);
}