Ubuntu 20.04 LTS : Tomcat vulnerabilities (USN-4596-1)

##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4596-1. The text
# itself is copyright (C) Canonical, Inc. See
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(141862);
  script_version("1.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  script_cve_id(
    "CVE-2020-9484",
    "CVE-2020-11996",
    "CVE-2020-13934",
    "CVE-2020-13935"
  );
  script_xref(name:"USN", value:"4596-1");
  script_xref(name:"CEA-ID", value:"CEA-2021-0004");

  script_name(english:"Ubuntu 20.04 LTS : Tomcat vulnerabilities (USN-4596-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in
the USN-4596-1 advisory.

  - When using Apache Tomcat versions 10.0.0-M1 to 10.0.0-M4, 9.0.0.M1 to 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to
    7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the
    server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is
    configured with sessionAttributeValueClassNameFilter=null (the default unless a SecurityManager is used)
    or a sufficiently lax filter to allow the attacker provided object to be deserialized; and d) the attacker
    knows the relative file path from the storage location used by FileStore to the file the attacker has
    control over; then, using a specifically crafted request, the attacker will be able to trigger remote code
    execution via deserialization of the file under their control. Note that all of conditions a) to d) must
    be true for the attack to succeed. (CVE-2020-9484)

  - A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to
    9.0.35 and 8.5.0 to 8.5.55 could trigger high CPU usage for several seconds. If a sufficient number of
    such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.
    (CVE-2020-11996)

  - An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56
    did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such
    requests were made, an OutOfMemoryException could occur leading to a denial of service. (CVE-2020-13934)

  - The payload length in a WebSocket frame was not correctly validated in Apache Tomcat 10.0.0-M1 to
    10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56 and 7.0.27 to 7.0.104. Invalid payload lengths could
    trigger an infinite loop. Multiple requests with invalid payload lengths could lead to a denial of
    service. (CVE-2020-13935)

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://ubuntu.com/security/notices/USN-4596-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-9484");

  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:"2020/05/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/10/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/10/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libtomcat9-embed-java");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libtomcat9-java");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat9-admin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat9-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat9-examples");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat9-user");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2020-2023 Canonical, Inc. / NASL script (C) 2020-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '20.04', 'pkgname': 'libtomcat9-embed-java', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'libtomcat9-java', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'tomcat9', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'tomcat9-admin', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'tomcat9-common', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'tomcat9-examples', 'pkgver': '9.0.31-1ubuntu0.1'},
    {'osver': '20.04', 'pkgname': 'tomcat9-user', 'pkgver': '9.0.31-1ubuntu0.1'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libtomcat9-embed-java / libtomcat9-java / tomcat9 / tomcat9-admin / etc');
}