I am using simple html tag to display images from imgur.com:
<img alt="Modern Dashboard Design" src="http://i.imgur.com/yst7lV9.png?1" style="height:550px; width:1024px" />
this was working few days back, but now it is not showing. Image is displaying on jsfiddle,but not displaying on this page:
http://www.ucom.my/p/admin-page-for-website-50
When you view the page source, you will find img tags.
What might be the reason?
Content Security Policy: The page’s settings blocked the loading of a resource at http://i.imgur.com/2qEeCDA.png (“default-src http://www.ucom.my”).
Content Security Policy: The page’s settings blocked the loading of a resource at http://i.imgur.com/yst7lV9.png?1 (“default-src http://www.ucom.my”).
Content Security Policy: The page’s settings blocked the loading of a resource at http://i.imgur.com/GAXEkpu.jpg (“default-src http://www.ucom.my”).
Content Security Policy: The page’s settings blocked the loading of a resource at self (“default-src http://www.ucom.my”).
This can be seen when opening the Firebug console.
You have this in your head:
<meta http-equiv="Content-Security-Policy" content="default-src 'self'">
This means you have deliberately blocked all requests to imgur or anywhere else. Change it to this:
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; img-src example.com;">
Or just remove it entirely.
A quick look in your console tells me you have a LOAD of security errors.
Refused to load the image 'http://i.imgur.com/GAXEkpu.jpg' because it
violates the following Content Security Policy directive: "default-src
'self'". Note that 'img-src' was not explicitly set, so 'default-src'
is used as a fallback.
And this happens because:
<meta http-equiv="Content-Security-Policy" content="default-src 'self'">
this line of code exists which disallows content from foreign sources.
Open your browser's developer tools. Look at the console. Read the error messages.
Refused to load the image 'http://i.imgur.com/GAXEkpu.jpg' because it violates the following Content Security Policy directive: "default-src 'self'". Note that 'img-src' was not explicitly set, so 'default-src' is used as a fallback.
You've included:
<meta http-equiv="Content-Security-Policy" content="default-src 'self'">
in your page, which bans the use of <img> elements with a src on a different domain.
Have a look to your browser inspector...
It says:
[Error] Refused to load http://i.imgur.com/2qEeCDA.png because it appears in neither the img-src directive nor the default-src directive of the Content Security Policy.
[Error] Refused to apply a stylesheet because its hash, its nonce, or 'unsafe-inline' appears in neither the style-src directive nor the default-src directive of the Content Security Policy. (admin-page-for-website-50, line 87)
[Error] Refused to load http://i.imgur.com/yst7lV9.png?1 because it appears in neither the img-src directive nor the default-src directive of the Content Security Policy.
[Error] Refused to apply a stylesheet because its hash, its nonce, or 'unsafe-inline' appears in neither the style-src directive nor the default-src directive of the Content Security Policy. (admin-page-for-website-50, line 89)
[Error] Refused to load http://i.imgur.com/GAXEkpu.jpg because it appears in neither the img-src directive nor the default-src directive of the Content Security Policy.
Related
I have configured s3 Static website + CloudFront with lambda#Edge + aws cognito.
When I open Cloudfront URL after authenticating with cognito it shows above errors that it is not able to load the page due to security issues.
Repo: https://github.com/qoomon/aws-s3-bucket-browser
Link to refer: https://medium.com/#saurishkar/setting-up-aws-http-authentication-on-cloudfront-s3-using-cognito-and-lambda-edge-166ee38d471e
added below line to HTML but still gives an error.
<meta http-equiv="Content-Security-Policy" content="default-src *; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline' 'unsafe-eval' * ">
Error: Content Security Policy: The page’s settings blocked the loading of a resource at inline (“script-src”)
Error Screenshot
Any help appreciated.
CSPs can be expressed in HTTP headers and in HTML <meta> tags, but HTTP headers trump <meta> tags.
If you added a CSP using a <meta> tag but you have CSP related error messages before, then you haven't done anything useful since the existing HTTP headers will override the <meta> tag.
Remove the <meta> tag again. Then change the HTTP headers.
I have a webpage in an iframe which contains a link to a foreign page with attributes target="_blank" rel="noopener". This link works well from the page itself and also from the iframe but only when called via context menu with the option open in new tab. A regular click opens a new tab and shows the correct URL but results in This page has been blocked by Opera ERR_BLOCKED_BY_CLIENT.
I looked around for help, disabled all addons to no avail and played the scenario in incognito mode as well, no change. The console on the error page shows VM589:1460 crbug/1173575, non-JS module files deprecated. This hint left me in the dark, however. I manipulated the attributes to target="_blank" rel="noopener" rel="noreferrer" or rel="noopener noreferrer" with no success. This all applies to Opera.
I tried Brave with the same result and error message, except Brave instead of Opera, of course. Edge joins the failure band. No surprise then to see This page has been blocked by Chrome proper as well.
This error applies to all PDF-file links from the iframe, normal external links work well. Firefox shows briefly PDF.js viewer in the new tab and then works normal. I had no chance to try links to YouTube or the like, but I guess there is ample evidence I hit a bug in the chrome PDF-rendering engine.
What to do? Who is interested in this bug and how to reach them? Or is there anything I can do in my code?
Browser use already longer time the Content Security Policy (CSP) to protect users from undesired content. The definition of undesired content can be made by the site owner. if the site owner hasn't done that, then some standard values are used, which are more restrictive.
The website https://content-security-policy.com/ explains it like this
What is Content-Security-Policy?
Content-Security-Policy is the name of a HTTP response header that modern browsers use to enhance the security of the document (or web page). The Content-Security-Policy header allows you to restrict how resources such as JavaScript, CSS, or pretty much anything that the browser loads.
Although it is primarily used as a HTTP response header, you can also apply it via a meta tag.
The term Content Security Policy is often abbreviated as CSP.
What types of attacks does Content-Security-Policy help mitigate?
CSP was first designed to reduce the attack surface of Cross Site Scripting (XSS) attacks, later versions of the spec also protect against other forms of attack such as Click Jacking.
In your case you have to configure two hurdles for the user:
The iframe, required rule:
frame-src 'self'
The PDF, required rule:
object-src 'self' blob;
Essentially it's relatively safe to allow most things with 'self' but it's always good to disallow elements that are not used at all on the site.
Your Content Security Policy should look similar to this, and should allow PDFs in iframes:
Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; object-src 'self' blob:; style-src 'self'; frame-src 'self';
The best is to configure the CSP in the server configuration. This is not possible for every site owner though, and it's possible to configure the CSP in meta tags too. You could add this to your site inside the head-tag:
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; object-src 'self' blob:; style-src 'self'; frame-src 'self'">
Setting the CSP in the server configuration is the stronger approach though:
https://content-security-policy.com/examples/meta/
Here are more examples, including CSP related server configuration for Apache Web Server and Nginx Webserver:
https://content-security-policy.com/examples/
EDIT
If the PDF is hosted on another domain, then the CSP has to adjusted differently, more openly.
Different options for sources are explained here:
https://content-security-policy.com/#source_list
The iframe, required rule has to be adjusted.
It should be restricted either to a special domain with *.example.com or to a nonce with 'nonce-rAnd0m'.
The PDF, required rule has to be adjusted, the same advise like for point 1. is applying.
So even the PDF is external then, it doesn't mean that everything could be injected somehow in the website.
Assumed you use the option with the domain *.example.com it would look like or similar to this then:
Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; object-src '*.example.com' blob:; style-src 'self'; frame-src '*.example.com'
Assumed you use the option with the nonce it would look like or similar to this then:
Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; object-src 'nonce-rAnd0m' blob:; style-src 'self'; frame-src 'nonce-rAnd0m'
I didn't test it, so slight adjustments might be required.
How can I add specific libraries (ES modules) fetched through Unpkg to my Content Security Policy (CSP) policy - i.e. without allowing everything from Unpkg?
For example, this is how I add provide one library:
<script
type="module"
src="https://unpkg.com/web-social-share#latest/dist/websocialshare/websocialshare.esm.js"></script>
I tried various solution such as https://unpkg.com/web-social-share#latest/* or https://unpkg.com/web-social-share#* for my script-src policy but all resulted in an error:
Refused to load the script 'https://unpkg.com/web-social-share#latest/dist/websocialshare/websocialshare.esm.js' because it violates the following Content Security Policy directive: "script-src 'self' ...
Anything that seems to work is allowing everything from Unpkg which I would like to avoid.
<meta
http-equiv="Content-Security-Policy"
content="default-src 'self';
script-src 'self' https://unpkg.com/;" />
This is available only in CSP level 3: https://www.w3.org/TR/CSP3/#external-hash. But unfortunately you'll still need to support level 2. You can however use Subresource Integrity in most browsers.
I have searched and I have seen many articles saying how the content security policy is for my benefit and it secures my application, but why is it so frustrating. Currently this is my meta tag and my content security policy settings
<meta
http-equiv="Content-Security-Policy"
content="default-src 'none'; script-src 'self' 'unsafe-inline'; connect-src 'self' https://polygon-rpc.com/ https://ipfs.infura.io:5001/api/v0/add?stream-channels=true&progress=false https://ipfs.infura.io:5001/api/v0/* img-src 'self'; style-src 'self' 'unsafe-inline'; base-uri 'self'; form-action 'self'; font-src 'self' https://fonts.gstatic.com;
"
/>
In my application, I connect to the polygon network, and users can upload files to IPFS. Now the problem is that although the above allows the successful upload of files, IPFS sends the url of the uploaded image to show the file preview to the user and the url changes on every request but that is blocked by CSP. So what I wanna know now is how to disable the goddamn thing completely. I don't want it, because if I had to manually add all external websites I call to the meta tag. That just seems stupid
I tried setting the content security policy from the server side using this, but it does not seem to do anything and only the settings from the meta tag in the react html file that works.
app.use(
contentSecurityPolicy({
useDefaults: true,
directives: {
defaultSrc: ["'none'"],
connectSrc: [
"'self'",
"https://polygon-rpc.com/",
"https://ipfs.infura.io:5001",
"https://ipfs.infura.io:5001/api/v0",
"https://ipfs.infura.io",
],
upgradeInsecureRequests: [],
},
reportOnly: false,
})
);
Its a MERN application hosted on heroku. So any idea how to go about that? Thanks
I tried setting the content security policy from the server side using this, but it does not seem to do anything and only the settings from the meta tag in the react html file that works.
As a result, you have 2 CSPs acting simultaneously - from the meta tag and from the HTTP header. All sources must pass through both CSPs, so the strictest rules from both CSPs will be applied as a result.
Use either a meta tag or an HTTP header.
IPFS sends the url of the uploaded image to show the file preview to the user and the url changes on every request but that is blocked by CSP.
It's enough to set img-src * to allow images from any host.
Note you have 2 errors in the CSP in the meta tag:
is missed semicolon ; before img-src 'self';. Fix it as ; img-src * data: blob:; to allow images from any sources including data:-Urls and blob:-Urls.
the https://ipfs.infura.io:5001/api/v0/* source is wrong because CSP does not support * in the path-part. Remove *.
I'm creating a mobile application using Apache Cordova/Adobe Phonegap, and this code snippet was automatically generated. It's giving me this error in the Console inside Google Chrome.
Refused to load the stylesheet
'https://fonts.googleapis.com/css?family=Open+Sans' because it
violates the following Content Security Policy directive: "style-src
'self' 'unsafe-inline'".
What exactly does this HTML meta element do?
<meta http-equiv="Content-Security-Policy" content="default-src * 'unsafe-inline'; style-src 'self' 'unsafe-inline'; media-src *" />
Short answer: If you want the https://fonts.googleapis.com/css?family=Open+Sans stylesheet to be loaded by browsers instead of blocked, then change the content value of the meta element so that it looks like this:
<meta http-equiv="Content-Security-Policy"
content="default-src * 'unsafe-inline';
style-src 'self' https://fonts.googleapis.com/ 'unsafe-inline'; media-src *" />
Longer explanation
That meta http-equiv="Content-Security-Policy" element provides a Content Security Policy that specifies some restrictions on what origin browsers can load the page assets from and what kinds of JavaScript and CSS content browsers will allow the page to specify inline.
As far as the specific part of those restrictions that’s relevant to the message you cite, it’s the restriction style-src 'self', which has the meaning “Only allow loading of external stylesheets from the same origin (same scheme+host+port) that the page is served from”.
So, because your page tries to load https://fonts.googleapis.com/css?family=Open+Sans—a stylesheet from a different origin than the page itself—and your meta http-equiv="Content-Security-Policy" includes a restriction that says “Don’t do that”, then browsers obey that restriction and refuse to load that stylesheet, and the message that you cite gets logged.
The <meta> tag provides Metadata (data about data) about the Web page. It's not displayed on the page, but it is parsed through by the browser.
Read more about the <meta> tag here.
Regarding the Meta tag in question, the Content-Security-Policy meta-tag allows you to reduce the risk of XSS attacks by allowing you to define where resources can be loaded from, preventing browsers from loading data from any other locations. This makes it harder for an attacker to inject malicious code to your site, as worded from this answer.