I have following string:
soqDi22c2_A-eY4ahWKJV6GAYgmuJBZ3poNNEixha1lOhXxxoucRuuzmcyDD_9ZYp_ECXRPbrBf6issNn23CUDJrh_A5L3Y5dHhB0o_U5Oq_j4rDCXOJ4Q==
It's a query parameter generated by form on a page. (This is done server-side in ASP.net) We are able to submit this form programatically and get the string we need (it just leads to a detail page of an object [realworld parcel/building, publicly accessible]) and redirect our user to it. However I would like to know, if there is a way to decrypt/deobfuscate this string to know what it contains and if we could possibly just generate these without going through the form (it's a multi step form).
The string also has some sort of expiration, so I sadly cannot provide a link to the result page, as it would stop working after like 10 minutes or so.
It feels a bit like it's base64, but after trying to run it through base64 -d, it says it's invalid.
It's likely base64 with + and / replaced with - and _ to make it more browser-friendly.
Though even if it's base64-encoded, it may just be a completely random key. You won't nessesarily be able to decode it to something readable.
Related
Making an ad manager plugin for WordPress, so the advertisement code can be almost anything, from good code to dirty, even evil.
I'm using simple sanitization like:
$get_content = '<script>/*code to destroy the site*/</script>';
//insert into db
$sanitized_code = addslashes( $get_content );
When viewing:
$fetched_data = /*slashed code*/;
//show as it's inserted
echo stripslashes( $fetched_data );
I'm avoiding base64_encode() and base64_decode() as I learned their performance is a bit slow.
Is that enough?
if not, what else I should ensure to protect the site and/or db from evil attack using bad ad code?
I'd love to get your explanation why you are suggestion something - it'll help deciding me the right thing in future too. Any help would be greatly appreciated.
addslashes then removeslashes is a round trip. You are echoing the original string exactly as it was submitted to you, so you are not protected at all from anything. '<script>/*code to destroy the site*/</script>' will be output exactly as-is to your web page, allowing your advertisers to do whatever they like in your web page's security context.
Normally when including submitted content in a web page, you should be using htmlspecialchars so that everything comes out as plain text and < just means a less then sign.
If you want an advertiser to be able to include markup, but not dangerous constructs like <script> then you need to parse the HTML, only allowing tags and attributes you know to be safe. This is complicated and difficult. Use an existing library such as HTMLPurifier to do it.
If you want an advertiser to be able to include markup with scripts, then you should put them in an iframe served from a different domain name, so they can't touch what's in your own page. Ads are usually done this way.
I don't know what you're hoping to do with addslashes. It is not the correct form of escaping for any particular injection context and it doesn't even remove difficult characters. There is almost never any reason to use it.
If you are using it on string content to build a SQL query containing that content then STOP, this isn't the proper way to do that and you will also be mangling your strings. Use parameterised queries to put data in the database. (And if you really can't, the correct string literal escape function would be mysql_real_escape_string or other similarly-named functions for different databases.)
Ok, I've been bugging with this for too long.
I need to call my website from a rough VB.net app. Then only thing I need is to attach a query string parameter to the calling url, so I can distinguish the pages to be shown to different VB app users.
So I want to click a button and launch that website, giving this parameter.
First I was bugging with adding the system.web libraries. Now I can't use Request/Response.QueryString as well.
I tried getting some example help from this post. but as I said before - I cannot make use of Request.QueryString as I cannot import it.
I am stuck here:
Process.Start("http://localhost:56093/WebSite1?id=")
I need to attach a query string parameter to the url and then open the website with that url.
Can someone just give me a sample code for my problem.
Query parameters are parsed by the web server/http handler off the URL you use to call the page. They consist of key and value pairs that come at the end of the URL. Your code is nearly there. Say you needed to pass through the parameters:
ID = 1234
Page = 2
Display = Portrait
Then you'd turn them into a URL like this:
http://localhost:56093/WebSite1?ID=1234&Page=2&Display=Portrait
Therefore in your code you'd have:
Process.Start("http://localhost:56093/WebSite1?ID=1234&Page=2&Display=Portrait");
I want to call a JSP with GET parameters within the GET parameter of a parent JSP. The URL for this would be http://server/getMap.jsp?lat=30&lon=-90&name=http://server/getName.jsp?lat1=30&lon1=-90
getName.jsp will return a string that goes in the name parameter of getMap.jsp.
I think the problem here is that &lon1=-90 at the end of the URL will be given to getMap.jsp instead of getName.jsp. Is there a way to distinguish which GET parameter goes to which URL?
One idea I had was to encode the second URL (e.g. = -> %3D and & -> %26) but that didn't work out well. My best idea so far is to allow only one parameter in the second URL, comma-delimited. So I'll have http://server/getMap.jsp?lat=30&lon=-90&name=http://server/getName.jsp?params=30,-90 and leave it up to getName.jsp to parse its variables. This way I leave the & alone.
NOTE - I know I can approach this problem from a completely different angle and avoid nested URLs altogether, but I still wonder (for the sake of knowledge!) if this is possible or if anyone has done it...
This has been done a lot, especially with ad serving technologies and URL redirects
But an encoded URL should just work fine. You need to completely encode it tho. A generator can be found here
So this:
http://server/getMap.jsp?lat=30&lon=-90&name=http://server/getName.jsp?lat1=30&lon1=-90
becomes this: http://server/getMap.jsp?lat=30&lon=-90&name=http%3A%2F%2Fserver%2FgetName.jsp%3Flat1%3D30%26lon1%3D-90
I am sure that jsp has a function for this. Look for "urlencode". Your JSP will see the contents of the GET-Variable "name" as the unencoded string: "http://server/getName.jsp?lat1=30&lon1=-90"
I am looking for some best practices when is comes to creating EditMoels and updating data in an ASP.NET MVC app. Lets say I have a Url like so /Post/Edit?Id=25
I am ensuring the user has permissions to edit the specific post by Id on the Get request and the same for my Post in the controller. I am using the ValidateAntiForgeryToken.
Questions: Should I include the Id property in my EditModel? If so, Should I encrypt it?
The problem is I can use FireBug to edit the Id hiddedinput and edit a different post as long as I have permission to do so. This is not horrible, but seems wrong.
Any help would be great!
There are several ways to prevent this.
The first - don't send sensitive data to the client at all. Keep the post id in session variables, so the user can never edit it. This may or may not be an option depending on your architecture.
The next approach is to convert the direct reference to an indirect one. For example, instead of sending postids = {23452, 57232, 91031} to the client to render a drop-down list, you should send an opaque list {1,2,3}. The server alone knows that 1 means 23452, 2 means 57232 and so on. This way, the user can't modify any parameter you don't want him to.
The last approach is including some kind of hash value that adds as an integrity check. For example, suppose you have 3 hidden fields in a html page - {userId=13223, postId=923, role=author}. You first sort the field names and then concatenate the values to get a string like postId=923&userId=13223&role=author. Then, append a server secret to this string, and hash (SHA-1 or MD5) the entire string. For eg. SHA-1('postId=923&userId=13223&role=author&MySuperSecretKey'). Finally add this hashed value as a hidden parameter. You may also want to add another hidden field called ProtectedParameters=userId,postId,role.
When the next request is made, redo the entire process. If the hash differs, balk the process.
Security wise, I have listed the options in decreasing order. At the same time, its probably in the increasing order of convenience. You have to pick the right mix for your application.
I don't think you should worry with that, if the user does what you said, i suppose that you'll know who edited what, so if he edits the wrong post, doing as you said, you can always remove his edition rights...
If you can't thrist your users, don't let them edit anything...
We use Captcha control in a registration form that we make full client validation for all fields in JavaScript ( JQuery ) beside server validation ..
I tried a lot of ways but all will write the Captcha value in JavaScript that can be accessed by anyone :(
I search if is there any way that allow me validate Captcha value in client side using JQuery in secure way or it can't be done ?
It cannot be done.
Javascript is client-side, as you know, and any code client-side has to be treated as potentially compromised as you don't have control over it.
At best, you could resort to sending up a salted hash of the value along with the salt, but even that in itself could be used to test guess values before actually submitting it.
Everything else relies on calls to the server.
As per comment request, here's the general idea:
Firstly, on the server, calculate a random string to be used as the salt. This should be roughly unique every request. The purpose of this string is to prevent rainbow table attacks.
Now, saving this string separately, but also create another string that is the concatenation of random string and the Captcha answer. Of this new combined string you generate the hash (for example, SHA-1) of it.
using System.Web.Security;
...
string hashVal = FormsAuthentication.HashPasswordForStoringInConfigFile(combined, "SHA1");
Both the random string and the hash value need to be placed in the page for the javascript to be able to read.
On the client side, when a user answers the Captcha, take the random string and concatenate it with the answer (getting the idea here?). Taking this string, you can use something like the SHA-1 JQuery plugin to hash it and compare it with the pre-computed hash you sent up.
hashVal = $.sha1(combinedString)
If it matches, it is (almost) certainly the correct answer. If it doesn't, then it is 100% the wrong answer.
you could use ajax to post the current value to the server, which would respond true or false. that would keep you from doing a real post and also from giving away the catpcha's value in html.
My solution )) Every time when page shows captcha to the user, you can dynamically generate obfuscated JavaScript functions(i think the best way 5 or 10).
For example, one function(or 3)) ) can set cookies with pregenerated hash(server returns it)(from real value of the captcha), other functions must realize server side algorithm to check value which user's typed. I can say that it works for 100%, because it is very hard to parse dynamically javascript + we set user cookies on client side(It is very hard for Bots's to find out where and how you set and check cookies), by using JavaScript.