Ubuntu 20.04 LTS : Squid vulnerabilities (USN-4477-1)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4477-1. 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(140031);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/23");

  script_cve_id("CVE-2020-15810", "CVE-2020-15811", "CVE-2020-24606");
  script_xref(name:"USN", value:"4477-1");
  script_xref(name:"IAVB", value:"2020-B-0050-S");

  script_name(english:"Ubuntu 20.04 LTS : Squid vulnerabilities (USN-4477-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"Amit Klein discovered that Squid incorrectly validated certain data. A
remote attacker could possibly use this issue to perform an HTTP
request smuggling attack, resulting in cache poisoning.
(CVE-2020-15810) Regis Leroy discovered that Squid incorrectly
validated certain data. A remote attacker could possibly use this
issue to perform an HTTP request splitting attack, resulting in cache
poisoning. (CVE-2020-15811) Lubos Uhliarik discovered that Squid
incorrectly handled certain Cache Digest response messages sent by
trusted peers. A remote attacker could possibly use this issue to
cause Squid to consume resources, resulting in a denial of service.
(CVE-2020-24606).

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-4477-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/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:N/AC:L/PR:L/UI:N/S:U/C:N/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-2020-15811");

  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:"2020/08/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/08/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/28");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:squid");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:squid-cgi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:squid-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:squid-purge");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:squidclient");
  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 (! ('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': 'squid', 'pkgver': '4.10-1ubuntu1.2'},
    {'osver': '20.04', 'pkgname': 'squid-cgi', 'pkgver': '4.10-1ubuntu1.2'},
    {'osver': '20.04', 'pkgname': 'squid-common', 'pkgver': '4.10-1ubuntu1.2'},
    {'osver': '20.04', 'pkgname': 'squid-purge', 'pkgver': '4.10-1ubuntu1.2'},
    {'osver': '20.04', 'pkgname': 'squidclient', 'pkgver': '4.10-1ubuntu1.2'}
];

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, 'squid / squid-cgi / squid-common / squid-purge / squidclient');
}