releases-comm-central/suite/mailnews/phishingDetector.js

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JavaScript

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Thunderbird Phishing Dectector
*
* The Initial Developer of the Original Code is
* The Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Scott MacGregor <mscott@mozilla.org>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ****** */
// Dependencies:
// gPrefBranch, gBrandBundle, gMessengerBundle should already be defined
// gatherTextUnder from utilityOverlay.js
const kPhishingNotSuspicious = 0;
const kPhishingWithIPAddress = 1;
const kPhishingWithMismatchedHosts = 2;
//////////////////////////////////////////////////////////////////////////////
// isEmailScam --> examines the message currently loaded in the message pane
// and returns true if we think that message is an e-mail scam.
// Assumes the message has been completely loaded in the message pane (i.e. OnMsgParsed has fired)
// aUrl: nsIURI object for the msg we want to examine...
//////////////////////////////////////////////////////////////////////////////
function isMsgEmailScam(aUrl)
{
var isEmailScam = false;
if (!aUrl || !gPrefBranch.getBoolPref("mail.phishing.detection.enabled"))
return isEmailScam;
// Ignore nntp and RSS messages
// nsIMsgMailNewsUrl.folder can throw an error, especially if we are opening
// a .eml message.
try {
var serverType = aUrl.folder.server.type;
if (serverType == 'nntp' || serverType == 'rss')
return isEmailScam;
} catch (ex) {}
// loop through all of the link nodes in the message's DOM, looking for phishing URLs...
var msgDocument = document.getElementById('messagepane').contentDocument;
var index;
// examine all links...
var linkNodes = msgDocument.links;
for (index = 0; index < linkNodes.length && !isEmailScam; index++)
isEmailScam = isPhishingURL(linkNodes[index], true);
// if an e-mail contains a non-addressbook form element, then assume the message is
// a phishing attack. Legitimate sites should not be using forms inside of e-mail
if (!isEmailScam)
{
var forms = msgDocument.getElementsByTagName("form");
for (index = 0; index < forms.length && !isEmailScam; index++)
isEmailScam = forms[index].action != "" && !/^addbook:/.test(forms[index].action);
}
// we'll add more checks here as our detector matures....
return isEmailScam;
}
//////////////////////////////////////////////////////////////////////////////
// isPhishingURL --> examines the passed in linkNode and returns true if we think
// the URL is an email scam.
// aLinkNode: the link node to examine
// aSilentMode: don't prompt the user to confirm
// aHref: optional href for XLinks
//////////////////////////////////////////////////////////////////////////////
function isPhishingURL(aLinkNode, aSilentMode, aHref)
{
if (!gPrefBranch.getBoolPref("mail.phishing.detection.enabled"))
return false;
var phishingType = kPhishingNotSuspicious;
var href = aHref || aLinkNode.href;
if (!href)
return false;
var linkTextURL = {};
var unobscuredHostName = {};
var isPhishingURL = false;
var ioService = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService);
var hrefURL = ioService.newURI(href, null, null);
// only check for phishing urls if the url is an http or https link.
// this prevents us from flagging imap and other internally handled urls
if (hrefURL.schemeIs('http') || hrefURL.schemeIs('https'))
{
unobscuredHostName.value = hrefURL.host;
if (hostNameIsIPAddress(hrefURL.host, unobscuredHostName) && !isLocalIPAddress(unobscuredHostName))
phishingType = kPhishingWithIPAddress;
else if (misMatchedHostWithLinkText(aLinkNode, hrefURL, linkTextURL))
phishingType = kPhishingWithMismatchedHosts;
isPhishingURL = phishingType != kPhishingNotSuspicious;
if (!aSilentMode && isPhishingURL) // allow the user to override the decision
isPhishingURL = confirmSuspiciousURL(phishingType, unobscuredHostName.value);
}
return isPhishingURL;
}
//////////////////////////////////////////////////////////////////////////////
// helper methods in support of isPhishingURL
//////////////////////////////////////////////////////////////////////////////
function misMatchedHostWithLinkText(aLinkNode, aHrefURL, aLinkTextURL)
{
var linkNodeText = gatherTextUnder(aLinkNode);
// gatherTextUnder puts a space between each piece of text it gathers,
// so strip the spaces out (see bug 326082 for details).
linkNodeText = linkNodeText.replace(/ /g, "");
// only worry about http and https urls
if (linkNodeText)
{
// does the link text look like a http url?
if (linkNodeText.search(/(^http:|^https:)/) != -1)
{
var ioService = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService);
var linkTextURL = ioService.newURI(linkNodeText, null, null);
aLinkTextURL.value = linkTextURL;
// compare hosts, but ignore possible www. prefix
return !(aHrefURL.host.replace(/^www\./, "") == aLinkTextURL.value.host.replace(/^www\./, ""));
}
}
return false;
}
// returns true if the hostName is an IP address
// if the host name is an obscured IP address, returns the unobscured host
function hostNameIsIPAddress(aHostName, aUnobscuredHostName)
{
// TODO: Add Support for IPv6
var index;
// scammers frequently obscure the IP address by encoding each component as octal, hex
// or in some cases a mix match of each. The IP address could also be represented as a DWORD.
// break the IP address down into individual components.
var ipComponents = aHostName.split(".");
// if we didn't find at least 4 parts to our IP address it either isn't a numerical IP
// or it is encoded as a dword
if (ipComponents.length < 4)
{
// Convert to a binary to test for possible DWORD.
var binaryDword = parseInt(aHostName).toString(2);
if (isNaN(binaryDword))
return false;
// convert the dword into its component IP parts.
ipComponents =
[
(aHostName >> 24) & 255,
(aHostName >> 16) & 255,
(aHostName >> 8) & 255,
(aHostName & 255)
];
}
else
{
for (index = 0; index < ipComponents.length; ++index)
{
// by leaving the radix parameter blank, we can handle IP addresses
// where one component is hex, another is octal, etc.
ipComponents[index] = parseInt(ipComponents[index]);
}
}
// make sure each part of the IP address is in fact a number
for (index = 0; index < ipComponents.length; ++index)
if (isNaN(ipComponents[index])) // if any part of the IP address is not a number, then we can safely return
return false;
// only set aUnobscuredHostName if we are looking at an IPv4 host name
var hostName = ipComponents.join(".");
if (isIPv4HostName(hostName))
{
aUnobscuredHostName.value = hostName;
return true;
}
return false;
}
function isIPv4HostName(aHostName)
{
var ipv4HostRegExp = new RegExp(/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/); // IPv4
// treat 0.0.0.0 as an invalid IP address
return ipv4HostRegExp.test(aHostName) && aHostName != '0.0.0.0';
}
// returns true if the user confirms the URL is a scam
function confirmSuspiciousURL(aPhishingType, aSuspiciousHostName)
{
var brandShortName = gBrandBundle.getString("brandShortName");
var titleMsg = gMessengerBundle.getString("confirmPhishingTitle");
var dialogMsg;
switch (aPhishingType)
{
case kPhishingWithIPAddress:
case kPhishingWithMismatchedHosts:
dialogMsg = gMessengerBundle.getFormattedString("confirmPhishingUrl" + aPhishingType, [brandShortName, aSuspiciousHostName], 2);
break;
default:
return false;
}
const nsIPS = Components.interfaces.nsIPromptService;
var promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(nsIPS);
var buttons = nsIPS.STD_YES_NO_BUTTONS + nsIPS.BUTTON_POS_1_DEFAULT;
return promptService.confirmEx(window, titleMsg, dialogMsg, buttons, "", "", "", "", {}); /* the yes button is in position 0 */
}
// returns true if the IP address is a local address.
function isLocalIPAddress(unobscuredHostName)
{
var ipComponents = unobscuredHostName.value.split(".");
return ipComponents[0] == 10 ||
(ipComponents[0] == 192 && ipComponents[1] == 168) ||
(ipComponents[0] == 169 && ipComponents[1] == 254) ||
(ipComponents[0] == 172 && ipComponents[1] >= 16 && ipComponents[1] < 32);
}