Vulnerabilities > CVE-2017-14417 - Missing Authentication for Critical Function vulnerability in Dlink Dir-850L Firmware

047910
CVSS 9.8 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
dlink
CWE-306
critical
nessus

Summary

register_send.php on D-Link DIR-850L REV. B (with firmware through FW208WWb02) devices does not require authentication, which can result in unintended enrollment in mydlink Cloud Services.

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Choosing a Message/Channel Identifier on a Public/Multicast Channel
    Attackers aware that more data is being fed into a multicast or public information distribution means can 'select' information bound only for another client, even if the distribution means itself forces users to authenticate in order to connect initially. Doing so allows the attacker to gain access to possibly privileged information, possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could change its identifier from a less privileged to more so privileged channel or command.
  • Using Unpublished Web Service APIs
    An attacker searches for and invokes Web Services APIs that the target system designers did not intend to be publicly available. If these APIs fail to authenticate requests the attacker may be able to invoke services and/or gain privileges they are not authorized for.
  • Manipulating Writeable Terminal Devices
    This attack exploits terminal devices that allow themselves to be written to by other users. The attacker sends command strings to the target terminal device hoping that the target user will hit enter and thereby execute the malicious command with their privileges. The attacker can send the results (such as copying /etc/passwd) to a known directory and collect once the attack has succeeded.
  • Cross Site Request Forgery (aka Session Riding)
    An attacker crafts malicious web links and distributes them (via web pages, email, etc.), typically in a targeted manner, hoping to induce users to click on the link and execute the malicious action against some third-party application. If successful, the action embedded in the malicious link will be processed and accepted by the targeted application with the users' privilege level. This type of attack leverages the persistence and implicit trust placed in user session cookies by many web applications today. In such an architecture, once the user authenticates to an application and a session cookie is created on the user's system, all following transactions for that session are authenticated using that cookie including potential actions initiated by an attacker and simply "riding" the existing session cookie.

Nessus

NASL familyCGI abuses
NASL idDLINK_MYDLINK_MISSING_AUTH.NASL
descriptionThe remote D-Link DIR router does not enforce authentication when a remote user requests register_send.php. An attacker can use this weakness to recover the administrator password.
last seen2020-06-01
modified2020-06-02
plugin id103219
published2017-09-14
reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/103219
titleD-Link DIR Router Missing Authentication Check
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(103219);
  script_version("1.5");
  script_cvs_date("Date: 2019/11/12");

  script_cve_id("CVE-2017-14417");

  script_name(english:"D-Link DIR Router Missing Authentication Check");
  script_summary(english:"Sends an HTTP GET request");

  script_set_attribute(attribute:"synopsis", value:
"The remote router doesn't properly enforce authentication");
  script_set_attribute(attribute:"description", value:
"The remote D-Link DIR router does not enforce authentication
when a remote user requests register_send.php. An attacker can
use this weakness to recover the administrator password.");
  # https://pierrekim.github.io/blog/2017-09-08-dlink-850l-mydlink-cloud-0days-vulnerabilities.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?32828524");
  script_set_attribute(attribute:"solution", value:
"No patch currently exists for this vulnerability");
  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:U/RC:ND");
  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:U/RC:X");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-14417");

  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:"2017/09/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/09/14");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("dlink_dir_www_detect.nbin");
  script_require_keys("installed_sw/DLink DIR");
  script_require_ports("Services/www", 80, 8080, 8181, 443, 8443);

  exit(0);
}

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

appname = 'DLink DIR';
get_install_count(app_name:appname, exit_if_zero:TRUE);
port = get_http_port(default:80, embedded:TRUE);
install = get_single_install(app_name:appname, port:port);

uri = '/register_send.php';
action = '?action=from_nessus';
res = http_send_recv3(
  method:'GET',
  item:uri + action,
  port:port,
  exit_on_fail:TRUE);

# Yes, authentication is misspelled.
if (empty_or_null(res) || "200 OK" >!< res[0] || "Authenication fail" >< res[2])
{
  audit(AUDIT_HOST_NOT, "an affected D-Link DIR router");
}

if ("<result>fail</result>" >< res[2])
{
  var report = 
    '\n' + "Nessus was able to access the following URL" +
    '\n' + "without authentication:" +
    '\n' +
    '\n' + build_url(qs:uri, port:port) +
    '\n' +
    '\n' + 'Access to this URL allows an attacker to recover' +
    '\n' + "the admin credentials through D-Link's mydlink" +
    '\n' + 'cloud service.' +
    '\n';
  security_report_v4(severity:SECURITY_HOLE, port:port, extra:report);
  exit(0);
}

# We haven't seen a patch yet. But we are going to assume if
# we hit this point then a patch has been released... and maybe
# they fixed their spelling error.
audit(AUDIT_HOST_NOT, "an affected D-Link DIR router");