Amazon Linux 2023 : python3-filelock (ALAS2023-2026-1415)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2026-1415.
##

include('compat.inc');

if (description)
{
  script_id(298128);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/14");

  script_cve_id("CVE-2025-68146", "CVE-2026-22701");

  script_name(english:"Amazon Linux 2023 : python3-filelock (ALAS2023-2026-1415)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1415 advisory.

    filelock is a platform-independent file lock for Python. In versions prior to 3.20.1, a Time-of-Check-
    Time-of-Use (TOCTOU) race condition allows local attackers to corrupt or truncate arbitrary user files
    through symlink attacks. The vulnerability exists in both Unix and Windows lock file creation where
    filelock checks if a file exists before opening it with O_TRUNC. An attacker can create a symlink pointing
    to a victim file in the time gap between the check and open, causing os.open() to follow the symlink and
    truncate the target file. All users of filelock on Unix, Linux, macOS, and Windows systems are impacted.
    The vulnerability cascades to dependent libraries. The attack requires local filesystem access and ability
    to create symlinks (standard user permissions on Unix; Developer Mode on Windows 10+). Exploitation
    succeeds within 1-3 attempts when lock file paths are predictable. The issue is fixed in version 3.20.1.
    If immediate upgrade is not possible, use SoftFileLock instead of UnixFileLock/WindowsFileLock (note:
    different locking semantics, may not be suitable for all use cases); ensure lock file directories have
    restrictive permissions (chmod 0700) to prevent untrusted users from creating symlinks; and/or monitor
    lock file directories for suspicious symlinks before running trusted applications. These workarounds
    provide only partial mitigation. The race condition remains exploitable. Upgrading to version 3.20.1 is
    strongly recommended. (CVE-2025-68146)

    filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition
    vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local
    filesystem access and permission to create symlinks can exploit a race condition between the permission
    validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability
    occurs in the _acquire() method between raise_on_not_writable_file() (permission check) and os.open()
    (file creation). During this race window, an attacker can create a symlink at the lock file path,
    potentially causing the lock to operate on an unintended target file or leading to denial of service. This
    issue has been patched in version 3.20.3. (CVE-2026-22701)

Tenable has extracted the preceding description block directly from the tested product 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://alas.aws.amazon.com//AL2023/ALAS2023-2026-1415.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-68146.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-22701.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update python-filelock --releasever 2023.10.20260202' or
  or 'dnf update --advisory ALAS2023-2026-1415 --releasever 2023.10.20260202' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:S/C:P/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:H/PR:L/UI:N/S:U/C:L/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-2025-68146");

  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:"2025/12/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/02/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/02/05");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python-filelock-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python3-filelock");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  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) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include("rpm.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 != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

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

var pkgs = [
    {'reference':'python-filelock-doc-3.3.1-1.amzn2023.0.2', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-filelock-3.3.1-1.amzn2023.0.2', 'release':'AL-2023', '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 = 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, "python-filelock-doc / python3-filelock");
}