Linux Distros Unpatched Vulnerability : CVE-2021-23336

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(223655);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/08/20");

  script_cve_id("CVE-2021-23336");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2021-23336");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before
    3.8.8, from 3.9.0 and before 3.9.2 are vulnerable to Web Cache Poisoning via urllib.parse.parse_qsl and
    urllib.parse.parse_qs by using a vector called parameter cloaking. When the attacker can separate query
    parameters using a semicolon (;), they can cause a difference in the interpretation of the request between
    the proxy (running with default configuration) and the server. This can result in malicious requests being
    cached as completely safe ones, as the proxy would usually not see the semicolon as a separator, and
    therefore would not include it in a cache key of an unkeyed parameter. (CVE-2021-23336)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2021-23336");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/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:R/S:U/C:N/I:L/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-23336");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/01/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/03/04");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  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:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python2.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.6");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.8");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

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

  script_dependencies("set_linux_os_id.nasl", "ssh_get_info2.nasl");
  script_require_keys("Host/OS/identifier", "Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched");
  script_require_ports("Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "idle-python2.7"},
          {"reference": "idle-python3.4"},
          {"reference": "libpython2.7"},
          {"reference": "libpython2.7-dbg"},
          {"reference": "libpython2.7-dev"},
          {"reference": "libpython2.7-minimal"},
          {"reference": "libpython2.7-stdlib"},
          {"reference": "libpython2.7-testsuite"},
          {"reference": "libpython3.4"},
          {"reference": "libpython3.4-dbg"},
          {"reference": "libpython3.4-dev"},
          {"reference": "libpython3.4-minimal"},
          {"reference": "libpython3.4-stdlib"},
          {"reference": "libpython3.4-testsuite"},
          {"reference": "python2.7"},
          {"reference": "python2.7-dbg"},
          {"reference": "python2.7-dev"},
          {"reference": "python2.7-doc"},
          {"reference": "python2.7-examples"},
          {"reference": "python2.7-minimal"},
          {"reference": "python3.4"},
          {"reference": "python3.4-dbg"},
          {"reference": "python3.4-dev"},
          {"reference": "python3.4-doc"},
          {"reference": "python3.4-examples"},
          {"reference": "python3.4-minimal"},
          {"reference": "python3.5"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "idle-python2.7"},
          {"reference": "idle-python3.5"},
          {"reference": "libpython2.7"},
          {"reference": "libpython2.7-dbg"},
          {"reference": "libpython2.7-dev"},
          {"reference": "libpython2.7-minimal"},
          {"reference": "libpython2.7-stdlib"},
          {"reference": "libpython2.7-testsuite"},
          {"reference": "libpython3.5"},
          {"reference": "libpython3.5-dbg"},
          {"reference": "libpython3.5-dev"},
          {"reference": "libpython3.5-minimal"},
          {"reference": "libpython3.5-stdlib"},
          {"reference": "libpython3.5-testsuite"},
          {"reference": "python2.7"},
          {"reference": "python2.7-dbg"},
          {"reference": "python2.7-dev"},
          {"reference": "python2.7-doc"},
          {"reference": "python2.7-examples"},
          {"reference": "python2.7-minimal"},
          {"reference": "python3.5"},
          {"reference": "python3.5-dbg"},
          {"reference": "python3.5-dev"},
          {"reference": "python3.5-doc"},
          {"reference": "python3.5-examples"},
          {"reference": "python3.5-minimal"},
          {"reference": "python3.5-venv"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "idle-python2.7"},
          {"reference": "idle-python3.6"},
          {"reference": "libpython2.7"},
          {"reference": "libpython2.7-dbg"},
          {"reference": "libpython2.7-dev"},
          {"reference": "libpython2.7-minimal"},
          {"reference": "libpython2.7-stdlib"},
          {"reference": "libpython2.7-testsuite"},
          {"reference": "libpython3.6"},
          {"reference": "libpython3.6-dbg"},
          {"reference": "libpython3.6-dev"},
          {"reference": "libpython3.6-minimal"},
          {"reference": "libpython3.6-stdlib"},
          {"reference": "libpython3.6-testsuite"},
          {"reference": "python2.7"},
          {"reference": "python2.7-dbg"},
          {"reference": "python2.7-dev"},
          {"reference": "python2.7-doc"},
          {"reference": "python2.7-examples"},
          {"reference": "python2.7-minimal"},
          {"reference": "python3.6"},
          {"reference": "python3.6-dbg"},
          {"reference": "python3.6-dev"},
          {"reference": "python3.6-doc"},
          {"reference": "python3.6-examples"},
          {"reference": "python3.6-minimal"},
          {"reference": "python3.6-venv"},
          {"reference": "python3.7"},
          {"reference": "python3.8"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "idle-python3.8"},
          {"reference": "libpython3.8"},
          {"reference": "libpython3.8-dbg"},
          {"reference": "libpython3.8-dev"},
          {"reference": "libpython3.8-minimal"},
          {"reference": "libpython3.8-stdlib"},
          {"reference": "libpython3.8-testsuite"},
          {"reference": "python2.7"},
          {"reference": "python3.8"},
          {"reference": "python3.8-dbg"},
          {"reference": "python3.8-dev"},
          {"reference": "python3.8-doc"},
          {"reference": "python3.8-examples"},
          {"reference": "python3.8-minimal"},
          {"reference": "python3.8-venv"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "python2.7"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}