Alibaba Cloud Linux 3 : 0023: flatpak (ALINUX3-SA-2021:0023)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# Alibaba Cloud Linux Security Advisory ALINUX3-SA-2021:0023.
##

include('compat.inc');

if (description)
{
  script_id(236596);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/05/14");

  script_cve_id("CVE-2021-21381");

  script_name(english:"Alibaba Cloud Linux 3 : 0023: flatpak (ALINUX3-SA-2021:0023)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Alibaba Cloud Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Alibaba Cloud Linux 3 host has packages installed that are affected by a vulnerability as referenced in the
ALINUX3-SA-2021:0023 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    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 Alibaba Cloud Linux security advisory.

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:"http://mirrors.aliyun.com/alinux/3/cve/alinux3-sa-20210023.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:"2021/03/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/04/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/05/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-libs-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-selinux");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-session-helper");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-session-helper-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-tests");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:flatpak-tests-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alibabacloud:alibaba_cloud_linux_3");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Alibaba Cloud Linux 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_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Alibaba/release", "Host/Alibaba/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm.inc');

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

if (!get_kb_item('Host/Alibaba/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Alibaba Cloud Linux', cpu);

var pkgs = [
    {'reference':'flatpak-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-debuginfo-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-debuginfo-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-debugsource-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-debugsource-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-devel-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-devel-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-libs-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-libs-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-libs-debuginfo-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-libs-debuginfo-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-selinux-1.6.2-6.1.al8', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-session-helper-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-session-helper-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-session-helper-debuginfo-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-session-helper-debuginfo-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-tests-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-tests-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-tests-debuginfo-1.6.2-6.1.al8', 'cpu':'aarch64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
    {'reference':'flatpak-tests-debuginfo-1.6.2-6.1.al8', 'cpu':'x86_64', 'release':'3', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
];

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 = 'Alibaba 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, 'flatpak / flatpak-debuginfo / flatpak-debugsource / flatpak-devel / etc');
}