Azure Linux 3.0 Security Update: kernel (CVE-2025-21718)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(295388);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/22");

  script_cve_id("CVE-2025-21718");

  script_name(english:"Azure Linux 3.0 Security Update: kernel (CVE-2025-21718)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Azure Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of kernel installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore,
affected by a vulnerability as referenced in the CVE-2025-21718 advisory.

  - In the Linux kernel, the following vulnerability has been resolved: net: rose: fix timer races against
    user threads Rose timers only acquire the socket spinlock, without checking if the socket is owned by one
    user thread. Add a check and rearm the timers if needed. BUG: KASAN: slab-use-after-free in
    rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 Read of size 2 at addr ffff88802f09b82a by task
    swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace:
    <IRQ> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
    print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489
    kasan_report+0x143/0x180 mm/kasan/report.c:602 rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174
    call_timer_fn+0x187/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline]
    __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
    run_timer_base kernel/time/timer.c:2439 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
    handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq
    kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30
    kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
    sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ> (CVE-2025-21718)

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://nvd.nist.gov/vuln/detail/CVE-2025-21718");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/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:H/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-2025-21718");

  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:"2025/02/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/03/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/22");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:bpftool");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-accessibility");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-gpu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-intree-amdgpu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-sound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:python3-perf");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:microsoft:azure_linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AzureLinux/release", "Host/AzureLinux/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/AzureLinux/release');
if (isnull(release) || 'Azure Linux' >!< release) audit(AUDIT_OS_NOT, 'Azure Linux');
var os_ver = pregmatch(pattern: "Azure Linux ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Azure Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^3([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Azure Linux 3.0', 'Azure Linux ' + os_ver);

if (!get_kb_item('Host/AzureLinux/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, 'Azure Linux', cpu);

var pkgs = [
    {'reference':'bpftool-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'bpftool-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-intree-amdgpu-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-intree-amdgpu-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', '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;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 'Azure Linux ' + 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 (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  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, cves:cves)) 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, 'bpftool / kernel / kernel-debuginfo / kernel-devel / kernel-docs / etc');
}