One of our clients received a social engineering warning from google. There is nothing hosted on the client's site and all I can assume is that the code is embedded in the URL. How can I stop this and make sure that the URL is not being taken advantage of?
Code below -
http://blog.essentialtech.com[.]au/events/public/v1/track/c/*W42X1Kh4VlKV7W4NDyrQ4Jwqwc0/*W34SKKS4FTw8nW7PlP8S8lBlFP0/5/f18dQhb0SfHC9dsQ84N7cW9rzHyjJqVS9MQR2B872gW3hHhb35zh-NRVnQ9Qq8Z_8m8W328bd38Xl1YFW2Mk5st5mZ50NMH5sdmJ4m23N8_dF8cJVPWRW4c2Tyb6d_m0TVHG2xy2R1bM2W2N6lzq4cj1_jW2pzD7d2MTPSyVKng6q1Wg4bjW58jf-C34RCjxW2p2f452LHP4rW5x5KNk7-XB_5N4Qzp5DMBCsfW7pKMHF2K4XMjW8tzC3F8q-1tCN1KKm4vRFkK4W5G18Kh3y9KYQN3dgtM7YrDrqW5hfJ425v5Cb1W8x-WCY3tg8kZN6p6WGsDLwCnW5BLL855GJB9nW5lW2Zn30_g8xW5kXBFn6n161-W38SQwr2Yy7gbW8Knjr38f7c2WW5rTvwF42SsX8W5nLxq_8r0-2RW30v4M38wyznpN3Gyjm6BNxmYW3gfMK48j556ZN8q1-LpjGXPKN64V3lHJRhw9VcZLWR86l4pCW8yq-Kr3rJTdsN5d_Q0Zj8tbNW480YZF3psJYWW8l-5SS6S8BxvW2RLxLy7X8G2fW5SdKBQ8s1s46W32wFFH1NsfDKSqhY367YLr102?_ud=617a5272-4c86-4d80-987a-d62228fd4f5e
This could be referring to a situation where in your code you're directly outputting the value of a query parameter or URL part in your page itself.
HubSpot has some automatic protections to prevent that kind of code injection, but there's still some best practices you should follow regardless of what CMS platform you're using.
Never trust query parameters as having only valid data. Never directly output it on the page. You can use HubL filters such as |escape and |striptags to remove potentially harmful code in the event you do need to display the value in the page.
An example of a time you might do that might be for a search results page, where you show "Search results for :"
I am using Requestly Chrome extension to intercept and modify HTTP request headers and change their original values inside my NodeJS app.
How can I prevent attack? For example, I can change Referer header and inject link.
There is no way to prevent users from doing this.
You can't trust the Referer header.
You cannot, but you can try to make the thing more difficult to do, thing a tricky way to sign the headers / datas (sha512, etc..) and add signature in the headers/cookie/datas.
Use the same function on your server to check if the value has been modified during the transport.
"But the 'hacker' can still try to inspect the client code and use the signature function to modify the values ?"
Yes, but you can transform the thing in something completely illisible:
Make your app include a bench of useless big script which doing nothing (uglified of course)
Divide your signature function in many (many) functions named with random char and then uglified them, put one of them inside your useless big scripts.
...
Nothing is trustable on client side, but you can try to discourage the hackers :D
Getting cross site scripting (XSS) issue in javascript file in veracode scan report.
It seems the issue is with innerHtml?
{
var b = document.createElement("div");
b.innerHTML = g.responseText;
for(var d=null,b=b.childNodes,e=0,h=b.length;e<h;++e)
{
var p=b[e];
);
In general, using innerHTML should be avoided unless you know exactly what you're doing.
I'm unfamiliar with Veracode, but I'd wager it's noticing that you're making a fetch request, then inserting data from the response directly into your page as code. It's sounding the alarm about this, as it should. Inserting XHR content directly as HTML is dangerous, as it could allow a malicious actor to execute code on your page in any of the following hypothetical scenarios:
You don't control the endpoint you're querying.Always assume that third-party data is malicious and act to secure your site accordingly.
You control the endpoint, but it becomes compromised.Envision the worst-case scenario, where a hacker breaks in and modifies the data you send to the client.
The endpoint returns unsanitized user input.A user could name themselves <script>alert(1);</script> and cause an alert to appear.
In any of these cases, it's possible for someone to insert a script or other content into a response, which, because you're using innerHTML, will be executed as HTML in the context of the page. This is a textbook example of an XSS (cross-site scripting) vulnerability. Hackers can (and very often do) use exploits like this for malicious purposes, including stealing the passwords, session cookies, and payment information of your end users. You're being warned in your code because hackers could potentially do the same thing to you.
If you're returning HTML code from your endpoint, firstly, don't. Return the data you want to put inside the elements in JSON format, then construct the elements yourself on the client side using document.createElement and Node.textContent. This will ensure that the data you return isn't interpreted as HTML code.
If you're retrieving static, non-HTML data from the endpoint, then you don't even need a workaround-- just switch innerHTML to textContent and you'll be on your way.
I was just researching, why using eval() function is bad and I found one reason to be vulnerable for code injection attacks (Post : Why is using the JavaScript eval function a bad idea?).
But my question is, do we necessarily need to be worried about the code injection in javascript? Because, if any user want to run any JS script for a website, he can do it by running in console.
So, I'm just wondering, what extra harm it may do, if anyone is successful to inject his code in my javascript code?
EDIT
Based on Oleander's answer below, I found one way of vulnerability when we have communications between the browser and the server through AJAX calls. That makes perfect sense. But I may have Javascript programs which only run in the browser and do not have any communications to the backend, for example a Calculator or a Simple Game. So my supplementary question here, is there any other reason which can make these programs vulnerable too?
Security problems occur when a hacker injects harmfull code into a JSON request made by a user, which is then evaluated using eval.
Imagine the following code is being ran
$.get("/get.json", function(data){
var obj = eval(data) // String to javascript object
});
The resource looks like this
GET /get.json
{
some: "data"
}
But an attacker replaces the above with using a man in the middle attack
function(){
// send window.cookie to attacker
}();
The attacker now have access to the users session.
Well if your code takes a value from the query string and uses it in an eval, an attacker could entice their victim to visit the URL containing the evil query string.
From OWASP:
<script>
function loadObj(){
var cc=eval('('+aMess+')');
document.getElementById('mess').textContent=cc.message;
}
if(window.location.hash.indexOf('message')==-1)
var aMess="({\"message\":\"Hello User!\"})";
else
var aMess=location.hash.substr(window.location.hash.indexOf('message=')+8);
</script>
The attacker could send an email containing a link or redirect a user visiting their malicious site to the URL
http://example.com/page.html?message=<img onerror="alert(xss)">
Then you have a DOM based XSS attack.
If your game with no backend is on a site with other sensitive information on it, such as user sessions, then it might be possible for the attacker to steal session cookies or grab credentials. It all depends on what the JavaScript has access to. That is, it will have full access to its hosting domain because the Same Origin Policy will restrict it to that. However, if you have other sensitive applications here then they could be compromised. If not, then at worst the attacker could abuse the trust a user has in your site by altering content or monitoring what users do on your site.
Imagine the next scenario: a user wants to register to a webpage and fills a form. While he is filling the form, jQuery keeps checking through a regular expression if fields are valid, etc...
Taking the email as the primary key which the user will use after registering to login, the email field needs to be checked with Ajax to let the user know if that email is registered or not. I want to check it with Ajax to avoid sending the full form and emptying it, refreshing page, etc...
So, when the user has ended filling the email field, the Ajax request is sent to the server, something like the next link:
example.com/check.php?email=abcdefg#gmail.com
When check.php receives the email, it asks the database if it exists or not and returns a message like: User already exists if user exists or null if user does not exist.
The question is: if someone digs through my .js and finds out links similar to that, they could use that link to send a large number of requests to find out if those random emails exist. This could lead to heavy use of the database or in the worst cases even crashing and private information leaks.
Someone could do a huge for loop to check emails like:
//Getting the response of the next links
example.com/check.php?email=aaaaaaa#gmail.com // Returns null
example.com/check.php?email=aaaaaab#gmail.com // Returns null
example.com/check.php?email=aaaaaac#gmail.com // Returns null
example.com/check.php?email=aaaaaad#gmail.com // Returns User already exists
------------------------------------------------------------------------------------------------------------------------------------
Since i last accepted the answer, i kept investigating this and found the solution to avoid this behaviour. The following code is for JAVA but the logic can be applied to any other server-side language.
Before doing ANY ajax request to the server, I request a token to the server. This token looks like this fmf5p81m6e56n4va3nkfu2ns8n it is made by a simple method, it can, however, be more complex, but this is good to go.
public String getToken() throws UnsupportedEncodingException {
return new BigInteger(130, new SecureRandom()).toString(32);
}
When requesting the token, the server does not only return the token, but also a small script that in case someone uses browser to inspect element (and browser navbar) and such the script will run and the token will be cleared. Servlet returns something like this:
_html += "<head>"
+ "<script> "
+ "window.onload=function(){\n"
+ " document.body.innerHTML = \"\";\n"
+ " }"
+ "window.location.href='http://mywebsite.com' "
+ "</script>"
+ "</head>"
+ "<body>"
+ "[" + token+ "]"
+ "</body>"
+ "</html>";
First empties the body then navigates back to wherever we want. javascript/jquery will however, catch the entire content as string, then I simply extract the string between [ and ]. This token is only available for the next request, so every AJAX request will have its unique token. On the 2nd reques the token just used is deleted.
After I get the token I append it as parameter to whatever link i request, something like this:
ajaxRequestObjet = $.ajax({
url: "http://localhost:8084/mywebsite.com/servlet", //<-- local tomcat server
method: "POST",
data: "type=AJAX&page=some-article&token=fmf5p81m6e56n4va3nkfu2ns8n"
});
This method works fine against someone who inspects the website manually and try to use the links, but what about java/php/IIS servers that do this automaticly?
For this ask for header! Something like this:
boolean isAjax = "XMLHttpRequest".equals(request.getHeader("X-Requested-With"));
It will be true only and only if XMLHttpRequest exists....
There is one last thing to keep in mind. Make sure 'Access-Control-Allow-Origin' header is NOT present in your app to make sure that any javascript NOT in your server wont get the server resources. If this header does not exist, chrome will return this:
XMLHttpRequest cannot load http://localhost:8084/mywebsite.com/servlet. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access.
Java server was in tomcat and I had another apache for this tests, this is the small html present in apache which gave the error above:
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
<script>
ajaxRequestObjet = $.ajax({
url: "http://localhost:8084/mywebsite.com/servlet",
method: "POST",
data: "type=AJAX&page=Token"
});
ajaxRequestObjet.done(function (msg) {
alert(msg);
});
</script>
</head>
<body>
</body>
</html>
While you can not control this 100%... there are a few options..
Try using the same methods that people use with Captcha scripts..
Basically when the user loads the form / page.. You generate a random string/id in their PHP session and store it.. When they send the ajax requests, have your ajax check also append the string/id and require it before allowing a check to perform else return a header of 500 or something..
Using this approach with sessions, you could set a allowed limit of checks (say 5) and once the user has tried more than 5 checks, They are required to reload the page or perform a human check (eg Captcha).. Then it resets their count.. Even allow a total of say 30 within 1 hour / per IP or something.
Also use smart events to trigger when the ajax check is done, eg field/tab change or on a button press.. Or when a valid email is detected.. but say .com.au would trigger twice.
Basically this way, even if someone sniffed your JS files and tried to automate the email checker.. It would require them finding a way to append the string/id that you generate and also limit their amount of requests performed.
Beyond this, there is not to much more you can do easily.. But there are still a few other idea's.
Most of them would work around using a PHP session / cookie.. Say for example if they check and find 3 email addresses.. Then again you set that as a limit and force them to require a manual submission or something.
See how the above suggestion goes for you, any questions do feel free to ask. But may take me a day or two to reply as weekend.. Also research how Captcha scripts work as plenty of source code for them.. As they work on the same idea.
Time Delays will simply look bad / make your site appear slow / bug the user with waiting for a response.
You need to limit the amount of look up's per session / ip address.. Otherwise there is always a way to get past these checks.. Basically once they hit a limit.. Force the user/ip/session to wait a few minutes/hours and verify them with a Captcha script so it can not be scripted...
Javascript Security / Hiding The Source
While you can not do this truly, you can do certain things generate the JS using a PHP page with a JS header.. so <script src='myjscode.php'></script> and this allows PHP to check for a valid session.. So stops external requests to an extent.. But this is mostly useful for allowing JS to be only available behind a membership/login..
Multiple Checks / If Possible In This Case
Depending on your approach, is this for a user to check if they already have an account? If so.. you could combine the email check with something like their name/country/age/dob ... So they would need to select two or three correct matching values before being able to get a check/response from the ajax call?
Maybe not in your case, but just thought would add this as well.
The JavaScript code on your website is executed on the computer of the user, so there is no way you could stop him from digging through your code. Even if you use a code obfuscator (for example, https://www.javascriptobfuscator.com/), the hacker could debug your application and record all requests send to the server.
Everything security-relevant has to happen on the server. You could limit the amount of requests from a specific IP address.
You could protect against brute force attacks with something similar to CSRF tokens:
Assign a server-generated ID to every client session. Each request to check.php should include this ID.
check.php should reject requests that do not include an ID, or include an ID that the server did not generate (to prevent attacks with spoofed IDs). It should also rate limit on ID - if a given ID has made a request in (say) the last second, or a given ID makes more than n requests in a 10 second interval, it should return an error response. This protects against requests from a single session arriving from several IP addresses.
You should also rate limit by IP address to prevent brute-forcing by opening a large number of web application sessions.
There isn't much you can do to prevent an attacker looking up a single, or small number, of specific email addresses - it's an inherent risk with this type of validation.
One approach to resolve this problem could be this:
Suppose you have ajax request calling your server to receive a response from a particular user or client. You can have a table in your database where you provide a unique token for every user or hash value that can be checked every time user makes an ajax request to the server. If the token value matches the user request value than he is a genuine user. You can also record his number of request on the table to ensure he is making legitimate requests. I acknowledge the fact that it may slow down your app performance, but it will be safe option to consider. Note: you need to retrieve the token on your HTML page to send it with ajax.
Please comment to know more. I have been using this approach and there is no problem until now.
Example:
This type of attack can be treated the same as any other brute force attack, where the only effective solution is to use a Captcha. But of course, Captchas are a detriment to UX, so you have to consider if the additional security is worth it, especially for an attack that is very unlikely to happen anyway. That said, you may want to use a Captcha on your registration form anyway, to prevent bots from creating accounts.
This sort of attack has a huge cost for little reward for the attacker. There are billions of possible email addresses to test for. It could only be worth going to great lengths such as this, if the site in question was particularly sensitive, such as some kind of adult site, where the attacker hopes to blackmail users that he finds.
CloudFlare
Not as good as a Captcha solution but the brute force attack might be detected and prevented by CloudFlare's DDoS system. Also, CF can force Tor users to solve a Captcha before accessing your site, which would prevent an attacker from using Tor as a vehicle for the attack.
IP Rate Limiting
Rate limiting on an IP basis has problems because if an attacker decided to undertake a task as huge as this, he will likely be using a Botnet or some other system of multiple machines to launch the attack.
Consider a large organisation such as a University, where all users share the public IP. One of the users launches an attack on your site, and you block his IP, and in the processes blocking everyone else. This countermeasure could actually be used to launch a DoS attack.
Session ID/CRSF Token
Definitely not a solution because the attacker needs to simply make a request to the page first, to obtain the token. It's an additional request to make but only an inconvenience for the attacker.
First of all: I'd URL-encode the mail-address. 'example.com/check.php?email=' . urlencode(abcdefg#gmail.com)
Ad your question: when check.php is called, you can
check, if the user's session and his IP have sent a request during the last seconds
if not, write the user's session, the user's IP plus the current timestamp to a helper-table plus to a cookie and hit your DB
if yes, block the request
But I'm afraid this won't help you from fraud because everyone can check your JavaScript and if someone want's to exploit this, he will find ways.
check.php should depending on the setup either only be accessible internally, or verify from where the connection is made. Take a look at this previous question- I hope it might be what you're looking for. how to verify the requesting server in php?
You could use a CSRF token and exit early from your script if you detect that no or an invalid CSRF token. Almost (if not all) PHP frameworks come with support for this.
Also check this question from the security community: https://security.stackexchange.com/questions/23371/csrf-protection-with-custom-headers-and-without-validating-token