TencentOS Server 3: flatpak (TSSA-2022:0244)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2022:0244.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(238649);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/20");

  script_cve_id("CVE-2021-21381", "CVE-2021-41133");

  script_name(english:"TencentOS Server 3: flatpak (TSSA-2022:0244)");

  script_set_attribute(attribute:"synopsis", value:
"The remote TencentOS Server 3 host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is,
therefore, affected by multiple vulnerabilities as referenced in the TSSA-2022:0244 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

      CVE-2021-41133:
      Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In
    versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AF_UNIX sockets such as those used
    by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into treating the
    Flatpak app as though it was an ordinary, non-sandboxed host-OS process. They can do this by manipulating
    the VFS using recent mount-related syscalls that are not blocked by Flatpak's denylist seccomp filter, in
    order to substitute a crafted `/.flatpak-info` or make that file disappear entirely. Flatpak apps that act
    as clients for AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can escalate the
    privileges that the corresponding services will believe the Flatpak app has. Note that protocols that
    operate entirely over the D-Bus session bus (user bus), system bus or accessibility bus are not affected
    by this. This is due to the use of a proxy process `xdg-dbus-proxy`, whose VFS cannot be manipulated by
    the Flatpak app, when interacting with these buses. Patches exist for versions 1.10.4 and 1.12.0, and as
    of time of publication, a patch for version 1.8.2 is being planned. There are no workarounds aside from
    upgrading to a patched version.

      CVE-2021-21381:
      Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In
    Flatpack since version 0.9.4 and before version 1.10.2 has a vulnerability in the file forwarding
    feature which can be used by an attacker to gain access to files that would not ordinarily be allowed by
    the app's permissions. By putting the special tokens `@@` and/or `@@u` in the Exec field of a Flatpak
    app's .desktop file, a malicious app publisher can trick flatpak into behaving as though the user had
    chosen to open a target file with their Flatpak app, which automatically makes that file available to the
    Flatpak app. This is fixed in version 1.10.2. A minimal solution is the first commit `Disallow @@ and @@U
    usage in desktop files`. The follow-up commits `dir: Reserve the whole @@ prefix` and `dir: Refuse to
    export .desktop files with suspicious uses of @@ tokens` are recommended, but not strictly required. As a
    workaround, avoid installing Flatpak apps from untrusted sources, or check the contents of the exported
    `.desktop` files in `exports/share/applications/*.desktop` (typically
    `~/.local/share/flatpak/exports/share/applications/*.desktop` and
    `/var/lib/flatpak/exports/share/applications/*.desktop`) to make sure that literal filenames do not follow
    `@@` or `@@u`.

Tenable has extracted the preceding description block directly from the Tencent Linux 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://mirrors.tencent.com/tlinux/errata/tssa-20220244.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N");
  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:N/UI:R/S:C/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-21381");

  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:"2022/12/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/12/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/06/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:tencent:tencentos_server:3");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:tencent:tencentos_server:flatpak");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}


include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'TencentOS' >!< os_product) audit(AUDIT_OS_NOT, 'TencentOS');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'TencentOS');
if (! preg(pattern:"^3([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'TencentOS 3.x', 'TencentOS ' + os_version);

if (!get_kb_item('Host/TencentOS/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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'TencentOS', cpu);

var constraints = [
  {
    'release': '3',
    'pkgs': [
      {'reference':'flatpak-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-debuginfo-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-debuginfo-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-debugsource-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-debugsource-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-devel-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-devel-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-libs-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-libs-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-libs-debuginfo-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-libs-debuginfo-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-selinux-1.10.7-1.tl3', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-session-helper-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-session-helper-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-session-helper-debuginfo-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-session-helper-debuginfo-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-tests-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-tests-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-tests-debuginfo-1.10.7-1.tl3', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-tests-debuginfo-1.10.7-1.tl3', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(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, 'flatpak / flatpak-debuginfo / flatpak-debugsource / etc');
}