Amazon Linux 2023 : gvfs, gvfs-archive, gvfs-client (ALAS2023-2026-3120)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2026-3120.
##

include('compat.inc');

if (description)
{
  script_id(351058);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/29");

  script_cve_id("CVE-2026-84268", "CVE-2026-88924");

  script_name(english:"Amazon Linux 2023 : gvfs, gvfs-archive, gvfs-client (ALAS2023-2026-3120)");

  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 ALAS2023-2026-3120 advisory.

    A flaw was found in the SFTP backend in gvfs. When mounting a share and reading a file, a malicious SFTP
    server can cause read_reply() to process a length that exceeds the size requested by the client. The
    function does not verify the server-provided length against the allocated buffer size, causing the
    operation to write past the intended boundaries. This issue allows a malicious server to corrupt adjacent
    heap memory in the gvfsd-sftp process, resulting in a denial of service as the process aborts upon
    detecting the heap corruption or potentially allowing arbitrary code execution. (CVE-2026-84268)

    A flaw was found in the admin backend of gvfs. The privileged gvfsd-admin daemon changes the ownership of
    newly created private D-Bus sockets by calling the link-following chown() function on a pathname inside a
    user-controlled directory. A local attacker can exploit this via a Time-of-Check Time-of-Use (TOCTOU) race
    condition and exchange the socket pathname with a symbolic link pointing to an arbitrary root-owned file
    (such as /etc/pam.d/su). The daemon subsequently follows the symlink and changes the ownership of the
    targeted root-owned file to the attacker's user ID. This allows an authenticated local attacker to modify
    critical system files, leading to a full local privilege escalation to root. (CVE-2026-88924)

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/ALAS2023-2026-3120.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-2026-84268.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-88924.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update gvfs --releasever 2023.12.20260928' or
  or 'dnf update --advisory ALAS2023-2026-3120 --releasever 2023.12.20260928' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/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:N/AC:L/PR:N/UI:R/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-2026-84268");

  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:"2026/09/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-archive");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-archive-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-client-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-fuse");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-fuse-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-goa");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-goa-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-nfs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-nfs-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-smb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-smb-debuginfo");
  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("rpm2.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':'gvfs-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debugsource-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debugsource-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-nfs-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-nfs-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-nfs-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-nfs-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-debuginfo-1.56.1-1.amzn2023.0.3', 'cpu':'x86_64', '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_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, "gvfs / gvfs-archive / gvfs-archive-debuginfo / etc");
}