Ubuntu 18.04 LTS : Python vulnerabilities (USN-5199-1)

2021-12-18T00:00:00
ID UBUNTU_USN-5199-1.NASL
Type nessus
Reporter Ubuntu Security Notice (C) 2021-2022 Canonical, Inc. / NASL script (C) 2021-2022 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2022-03-16T00:00:00

Description

The remote Ubuntu 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5199-1 advisory.

  • A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop, consuming CPU time. The highest threat from this vulnerability is to system availability. (CVE-2021-3737)

  • There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability. (CVE-2021-3733)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

                                        
                                            #%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-5199-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

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

if (description)
{
  script_id(156168);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/03/16");

  script_cve_id("CVE-2021-3733", "CVE-2021-3737");
  script_xref(name:"USN", value:"5199-1");

  script_name(english:"Ubuntu 18.04 LTS : Python vulnerabilities (USN-5199-1)");

  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 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in
the USN-5199-1 advisory.

  - A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may
    allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop,
    consuming CPU time. The highest threat from this vulnerability is to system availability. (CVE-2021-3737)

  - There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP
    server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of
    Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the
    server to the client. The greatest threat that this flaw poses is to application availability.
    (CVE-2021-3733)

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-5199-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C");
  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:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3737");

  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:"2021/09/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/12/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/12/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:idle-python3.6");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpython3.6");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpython3.6-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpython3.6-minimal");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpython3.6-stdlib");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libpython3.6-testsuite");
  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:python3.6-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.6-examples");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.6-minimal");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3.6-venv");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2021-2022 Canonical, Inc. / NASL script (C) 2021-2022 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('audit.inc');
include('ubuntu.inc');
include('misc_func.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/Ubuntu/release');
if ( isnull(release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
var release = chomp(release);
if (! preg(pattern:"^(18\.04)$", string:release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04', 'Ubuntu ' + 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$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);


var pkgs = [
    {'osver': '18.04', 'pkgname': 'idle-python3.6', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'libpython3.6', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'libpython3.6-dev', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'libpython3.6-minimal', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'libpython3.6-stdlib', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'libpython3.6-testsuite', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'python3.6', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'python3.6-dev', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'python3.6-examples', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'python3.6-minimal', 'pkgver': '3.6.9-1~18.04ubuntu1.6'},
    {'osver': '18.04', 'pkgname': 'python3.6-venv', 'pkgver': '3.6.9-1~18.04ubuntu1.6'}
];

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, 'idle-python3.6 / libpython3.6 / libpython3.6-dev / etc');
}