Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Apache HTTP Server vulnerabilities (USN-4458-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4458-1. 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(139596);
  script_version("1.12");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/20");

  script_cve_id(
    "CVE-2020-11984",
    "CVE-2020-11993",
    "CVE-2020-1927",
    "CVE-2020-1934",
    "CVE-2020-9490"
  );
  script_xref(name:"USN", value:"4458-1");
  script_xref(name:"IAVA", value:"2020-A-0376-S");
  script_xref(name:"CEA-ID", value:"CEA-2021-0025");
  script_xref(name:"CEA-ID", value:"CEA-2021-0004");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Apache HTTP Server vulnerabilities (USN-4458-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"Fabrice Perez discovered that the Apache mod_rewrite module
incorrectly handled certain redirects. A remote attacker could
possibly use this issue to perform redirects to an unexpected URL.
(CVE-2020-1927) Chamal De Silva discovered that the Apache
mod_proxy_ftp module incorrectly handled memory when proxying to a
malicious FTP server. A remote attacker could possibly use this issue
to obtain sensitive information. (CVE-2020-1934) Felix Wilhelm
discovered that the HTTP/2 implementation in Apache did not properly
handle certain Cache-Digest headers. A remote attacker could possibly
use this issue to cause Apache to crash, resulting in a denial of
service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04
LTS. (CVE-2020-9490) Felix Wilhelm discovered that the Apache
mod_proxy_uwsgi module incorrectly handled large headers. A remote
attacker could use this issue to obtain sensitive information or
possibly execute arbitrary code. This issue only affected Ubuntu 20.04
LTS. (CVE-2020-11984) Felix Wilhelm discovered that the HTTP/2
implementation in Apache did not properly handle certain logging
statements. A remote attacker could possibly use this issue to cause
Apache to crash, resulting in a denial of service. This issue only
affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-11993).

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-4458-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:N/AC:L/PR:N/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-2020-11984");

  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:"2020/04/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/08/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-bin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-data");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-ssl-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-suexec-custom");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-suexec-pristine");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache2-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libapache2-mod-md");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libapache2-mod-proxy-uwsgi");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  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:"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 (! ('16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 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': '16.04', 'pkgname': 'apache2', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-bin', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-data', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-dev', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-suexec-custom', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-suexec-pristine', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '16.04', 'pkgname': 'apache2-utils', 'pkgver': '2.4.18-2ubuntu3.17'},
    {'osver': '18.04', 'pkgname': 'apache2', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-bin', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-data', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-dev', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-ssl-dev', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-suexec-custom', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-suexec-pristine', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '18.04', 'pkgname': 'apache2-utils', 'pkgver': '2.4.29-1ubuntu4.14'},
    {'osver': '20.04', 'pkgname': 'apache2', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-bin', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-data', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-dev', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-ssl-dev', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-suexec-custom', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-suexec-pristine', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'apache2-utils', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'libapache2-mod-md', 'pkgver': '2.4.41-4ubuntu3.1'},
    {'osver': '20.04', 'pkgname': 'libapache2-mod-proxy-uwsgi', 'pkgver': '2.4.41-4ubuntu3.1'}
];

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_HOLE,
    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, 'apache2 / apache2-bin / apache2-data / apache2-dev / etc');
}