Puppet Symlink File Overwrite

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

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

if (description)
{
  script_id(72151);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/19");

  script_cve_id("CVE-2013-4969");
  script_bugtraq_id(64552);

  script_name(english:"Puppet Symlink File Overwrite");
  script_summary(english:"Checks puppet version");

  script_set_attribute(
    attribute:"synopsis",
    value:
"A web application on the remote host is potentially affected by a file
overwrite vulnerability."
  );
  script_set_attribute(
    attribute:"description",
    value:
"According to its self-reported version number, the Puppet install on
the remote host is potentially affected by an error related to temporary
files and their use.  A local attacker could potentially use a symlink
attack to overwrite arbitrary files."
  );
  script_set_attribute(attribute:"see_also", value:"https://puppet.com/security/cve/cve-2013-4969");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Puppet 3.3.3 / 3.4.1 or Puppet Enterprise 2.8.4 / 3.1.1 or
later.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No exploit is required");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2013/12/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2013/12/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/01/27");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:puppetlabs:puppet");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2014-2021 Tenable Network Security, Inc.");

  script_dependencies("puppet_rest_detect.nasl");
  script_require_keys("puppet/rest_port");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("http.inc");

##
# checks if the given version falls between the given bounds, and
# generates plugin output if it does
#
# @anonparam ver version to check
# @anonparam fix first fixed version
# @anonparam min_ver the lowest/earliest vulnerable version, relative to 'fix' (optional)
#
# @return plugin output if 'ver' is vulnerable relative to 'fix' and/or 'min_ver',
#         NULL otherwise
##
function _check_version(enterprise)
{
  local_var ver, fix, min_ver, major_ver, report;
  ver = _FCT_ANON_ARGS[0];
  fix = _FCT_ANON_ARGS[1];
  min_ver = _FCT_ANON_ARGS[2];

  if (
    # no lower bound
    (isnull(min_ver) &&
     ver_compare(ver:ver, fix:fix, strict:FALSE) < 0) ||

    # lower bound
    (!isnull(min_ver) &&
     ver_compare(ver:ver, fix:fix, strict:FALSE) < 0 &&
     ver_compare(ver:ver, fix:min_ver, strict:FALSE) >= 0)
  )
  {
    if (enterprise)
    {
      report =
        '\n  Installed version : Puppet Enterprise ' + ver +
        '\n  Fixed version     : Puppet Enterprise ' + fix + '\n';
    }
    else
    {
      report =
        '\n  Installed version : Puppet Open Source ' + ver +
        '\n  Fixed version     : Puppet Open Source ' + fix + '\n';
    }
  }
  else report = NULL;

  return report;
}

port = get_kb_item_or_exit('puppet/rest_port');
ver = get_kb_item_or_exit('puppet/' + port + '/version');
report = NULL;
vuln = FALSE;

if ('Enterprise' >< ver)
{
  # convert something like
  #   2.7.19 (Puppet Enterprise 2.7.0)
  # to
  #   2.7.0
  match = eregmatch(string:ver, pattern:"Enterprise ([0-9.]+)\)");
  if (isnull(match)) audit(AUDIT_UNKNOWN_WEB_APP_VER, 'Puppet Enterprise', build_url(port:port));
  ver = match[1];

  # Resolved in Puppet Enterprise 2.8.4 and 3.1.1
  if (
    (report = _check_version(ver, '2.8.4', enterprise:TRUE)) ||
    (report = _check_version(ver, '3.1.1', '3.1', enterprise:TRUE))
  ) vuln = TRUE;
}
else
{
  # Do not run against open source unless scan is paranoid
  if (report_paranoia < 2) audit(AUDIT_PARANOID);

  # sanity check - make sure the version doesn't include letters or anything else unexpected
  match = eregmatch(string:ver, pattern:"^([0-9.]+)$");
  if (isnull(match))  audit(AUDIT_NONNUMERIC_VER, 'Puppet', port, ver);
  ver = match[1];

  # Resolved in Puppet 3.3.3, 3.4.1
  if (
    (report = _check_version(ver, '3.3.3')) ||
    (report = _check_version(ver, '3.4.1', '3.4'))
  ) vuln = TRUE;
}

if (!vuln) audit(AUDIT_LISTEN_NOT_VULN, 'Puppet', port, ver);

if (report_verbosity > 0) security_note(port:port, extra:report);
else security_note(port);