AlmaLinux 8 : nginx:1.20 (ALSA-2022:0323)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The package checks in this plugin were extracted from
# AlmaLinux Security Advisory ALSA-2022:0323.
##

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

if (description)
{
  script_id(158864);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/01/13");

  script_cve_id("CVE-2021-23017");
  script_xref(name:"ALSA", value:"2022:0323");
  script_xref(name:"IAVB", value:"2021-B-0031");

  script_name(english:"AlmaLinux 8 : nginx:1.20 (ALSA-2022:0323)");

  script_set_attribute(attribute:"synopsis", value:
"The remote AlmaLinux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote AlmaLinux 8 host has packages installed that are affected by a vulnerability as referenced in the
ALSA-2022:0323 advisory.

    * nginx: Off-by-one in ngx_resolver_copy() when labels are followed by a pointer to a root domain name
    (CVE-2021-23017)

Tenable has extracted the preceding description block directly from the AlmaLinux 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:"https://errata.almalinux.org/8/ALSA-2022-0323.html");
  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:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-23017");

  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:"2021/05/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/01/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/03/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-all-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-filesystem");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-mod-http-image-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-mod-http-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-mod-http-xslt-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-mod-mail");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:nginx-mod-stream");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:8");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2022-2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AlmaLinux/release", "Host/AlmaLinux/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/AlmaLinux/release');
if (isnull(os_release) || 'AlmaLinux' >!< os_release) audit(AUDIT_OS_NOT, 'AlmaLinux');
var os_ver = pregmatch(pattern: "AlmaLinux release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'AlmaLinux');
os_ver = os_ver[1];
if (! preg(pattern:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'AlmaLinux 8.x', 'AlmaLinux ' + os_ver);

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

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'ppc' >!< cpu && 's390' >!< cpu && 'x86_64' >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'AlmaLinux', cpu);

var module_ver = get_kb_item('Host/AlmaLinux/appstream/nginx');
if (isnull(module_ver)) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module nginx:1.20');
if ('1.20' >!< module_ver) audit(AUDIT_PACKAGE_NOT_AFFECTED, 'Module nginx:' + module_ver);

var appstreams = {
    'nginx:1.20': [
      {'reference':'nginx-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-all-modules-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-filesystem-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-image-filter-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-perl-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-xslt-filter-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-mail-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-stream-1.20.1-1.module_el8.5.0+2611+ab304644.alma', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'}
    ]
};

var flag = 0;
var appstreams_found = 0;
foreach var module (keys(appstreams)) {
  var appstream = NULL;
  var appstream_name = NULL;
  var appstream_version = NULL;
  var appstream_split = split(module, sep:':', keep:FALSE);
  if (!empty_or_null(appstream_split)) {
    appstream_name = appstream_split[0];
    appstream_version = appstream_split[1];
    if (!empty_or_null(appstream_name)) appstream = get_one_kb_item('Host/AlmaLinux/appstream/' + appstream_name);
  }
  if (!empty_or_null(appstream) && appstream_version == appstream || appstream_name == 'all') {
    appstreams_found++;
    foreach var package_array ( appstreams[module] ) {
      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 = 'Alma-' + 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 (!appstreams_found) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module nginx:1.20');

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, 'nginx / nginx-all-modules / nginx-filesystem / etc');
}