Vulnerability findings for the public-facing infrastructure of telegram.org

Phase: Architecture and Design

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, use anti-CSRF packages such as the OWASP CSRFGuard.

Phase: Implementation

Ensure that your application is free of cross-site scripting issues, because most CSRF defenses can be bypassed using attacker-controlled script.

Phase: Architecture and Design

Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).

Note that this can be bypassed using XSS.

Identify especially dangerous operations. When the user performs a dangerous operation, send a separate confirmation request to ensure that the user intended to perform that operation.

Note that this can be bypassed using XSS.

Use the ESAPI Session Management control.

This control includes a component for CSRF.

Do not use the GET method for any request that triggers a state change.

Phase: Implementation

Check the HTTP Referer header to see if the request originated from an expected page. This could break legitimate functionality, because users or proxies may have disabled sending the Referer for privacy reasons.

• https://cheatsheetseries.owasp.org/cheatsheets/Cross-Site_Request_Forgery_Prevention_Cheat_Sheet.html
• https://cwe.mitre.org/data/definitions/352.html

Ensure that your web server, application server, load balancer, etc. is configured to set the Content-Security-Policy header.

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CSP
• https://cheatsheetseries.owasp.org/cheatsheets/Content_Security_Policy_Cheat_Sheet.html
• https://www.w3.org/TR/CSP/
• https://w3c.github.io/webappsec-csp/
• https://web.dev/articles/csp
• https://caniuse.com/#feat=contentsecuritypolicy
• https://content-security-policy.com/

Ensure that sensitive data is not available in an unauthenticated manner (using IP address white-listing, for instance).

Configure the "Access-Control-Allow-Origin" HTTP header to a more restrictive set of domains, or remove all CORS headers entirely, to allow the web browser to enforce the Same Origin Policy (SOP) in a more restrictive manner.

• https://vulncat.fortify.com/en/detail?category=HTML5&subcategory=Overly%20Permissive%20CORS%20Policy

Ensure that application Source Code is not available with alternative extensions, and ensure that source code is not present within other files or data deployed to the web server, or served by the web server.

• https://nhimg.org/twitter-breach

Provide a valid integrity attribute to the tag.

• https://developer.mozilla.org/en-US/docs/Web/Security/Defenses/Subresource_Integrity

Upgrade to the latest version of the affected library.

• https://owasp.org/Top10/A06_2021-Vulnerable_and_Outdated_Components/

Whenever a cookie contains sensitive information or is a session token, then it should always be passed using an encrypted channel. Ensure that the secure flag is set for cookies containing such sensitive information.

• https://owasp.org/www-project-web-security-testing-guide/v41/4-Web_Application_Security_Testing/06-Session_Management_Testing/02-Testing_for_Cookies_Attributes.html

Ensure that the SameSite attribute is set to either 'lax' or ideally 'strict' for all cookies.

• https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-cookie-same-site

Ensure that the SameSite attribute is set to either 'lax' or ideally 'strict' for all cookies.

• https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-cookie-same-site

Ensure JavaScript source files are loaded from only trusted sources, and the sources can't be controlled by end users of the application.

Ensure that the application/web server sets the Cross-Origin-Embedder-Policy header appropriately, and that it sets the Cross-Origin-Embedder-Policy header to 'require-corp' for documents.

If possible, ensure that the end user uses a standards-compliant and modern web browser that supports the Cross-Origin-Embedder-Policy header (https://caniuse.com/mdn-http_headers_cross-origin-embedder-policy).

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cross-Origin-Embedder-Policy

Ensure that the application/web server sets the Cross-Origin-Opener-Policy header appropriately, and that it sets the Cross-Origin-Opener-Policy header to 'same-origin' for documents.

'same-origin-allow-popups' is considered as less secured and should be avoided.

If possible, ensure that the end user uses a standards-compliant and modern web browser that supports the Cross-Origin-Opener-Policy header (https://caniuse.com/mdn-http_headers_cross-origin-opener-policy).

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cross-Origin-Opener-Policy

Ensure that the application/web server sets the Cross-Origin-Resource-Policy header appropriately, and that it sets the Cross-Origin-Resource-Policy header to 'same-origin' for all web pages.

'same-site' is considered as less secured and should be avoided.

If resources must be shared, set the header to 'cross-origin'.

If possible, ensure that the end user uses a standards-compliant and modern web browser that supports the Cross-Origin-Resource-Policy header (https://caniuse.com/mdn-http_headers_cross-origin-resource-policy).

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cross-Origin-Embedder-Policy

See the references for security advice on the use of these functions.

• https://v17.angular.io/guide/security

Configure the server to prevent such information leaks. For example:

Under Tomcat this is done via the "server" directive and implementation of custom error pages.

Under Apache this is done via the "ServerSignature" and "ServerTokens" directives.

• https://owasp.org/www-project-web-security-testing-guide/v41/4-Web_Application_Security_Testing/08-Testing_for_Error_Handling/

Ensure that your web server, application server, load balancer, etc. is configured to set the Permissions-Policy header.

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Permissions-Policy
• https://developer.chrome.com/blog/feature-policy/
• https://scotthelme.co.uk/a-new-security-header-feature-policy/
• https://w3c.github.io/webappsec-feature-policy/
• https://www.smashingmagazine.com/2018/12/feature-policy/

Ensure that your web server, application server, load balancer, etc. is configured to suppress the "Server" header or provide generic details.

• https://httpd.apache.org/docs/current/mod/core.html#servertokens
• https://learn.microsoft.com/en-us/previous-versions/msp-n-p/ff648552(v=pandp.10)
• https://www.troyhunt.com/shhh-dont-let-your-response-headers/

Ensure that your web server, application server, load balancer, etc. is configured to enforce Strict-Transport-Security.

• https://cheatsheetseries.owasp.org/cheatsheets/HTTP_Strict_Transport_Security_Cheat_Sheet.html
• https://owasp.org/www-community/Security_Headers
• https://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security
• https://caniuse.com/stricttransportsecurity
• https://datatracker.ietf.org/doc/html/rfc6797

Manually confirm that the timestamp data is not sensitive, and that the data cannot be aggregated to disclose exploitable patterns.

• https://cwe.mitre.org/data/definitions/200.html

Ensure that the application/web server sets the Content-Type header appropriately, and that it sets the X-Content-Type-Options header to 'nosniff' for all web pages.

If possible, ensure that the end user uses a standards-compliant and modern web browser that does not perform MIME-sniffing at all, or that can be directed by the web application/web server to not perform MIME-sniffing.

• https://learn.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/compatibility/gg622941(v=vs.85)
• https://owasp.org/www-community/Security_Headers

Do not allow user input to control cookie names and values. If some query string parameters must be set in cookie values, be sure to filter out semicolon's that can serve as name/value pair delimiters.

• https://en.wikipedia.org/wiki/HTTP_cookie
• https://cwe.mitre.org/data/definitions/565.html

Remove all comments that return information that may help an attacker and fix any underlying problems they refer to.

This is an informational alert and so no changes are required.

The content may be marked as storable by ensuring that the following conditions are satisfied:

The request method must be understood by the cache and defined as being cacheable ("GET", "HEAD", and "POST" are currently defined as cacheable)

The response status code must be understood by the cache (one of the 1XX, 2XX, 3XX, 4XX, or 5XX response classes are generally understood)

The "no-store" cache directive must not appear in the request or response header fields

For caching by "shared" caches such as "proxy" caches, the "private" response directive must not appear in the response

For caching by "shared" caches such as "proxy" caches, the "Authorization" header field must not appear in the request, unless the response explicitly allows it (using one of the "must-revalidate", "public", or "s-maxage" Cache-Control response directives)

In addition to the conditions above, at least one of the following conditions must also be satisfied by the response:

It must contain an "Expires" header field

It must contain a "max-age" response directive

For "shared" caches such as "proxy" caches, it must contain a "s-maxage" response directive

It must contain a "Cache Control Extension" that allows it to be cached

It must have a status code that is defined as cacheable by default (200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501).

• https://datatracker.ietf.org/doc/html/rfc7234
• https://datatracker.ietf.org/doc/html/rfc7231
• https://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html

For secure content, ensure the cache-control HTTP header is set with "no-cache, no-store, must-revalidate". If an asset should be cached consider setting the directives "public, max-age, immutable".

• https://cheatsheetseries.owasp.org/cheatsheets/Session_Management_Cheat_Sheet.html#web-content-caching
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cache-Control
• https://grayduck.mn/2021/09/13/cache-control-recommendations/

This is an informational alert rather than a vulnerability and so there is nothing to fix.

• https://www.zaproxy.org/docs/desktop/addons/authentication-helper/session-mgmt-id/

Validate that the response does not contain sensitive, personal or user-specific information. If it does, consider the use of the following HTTP response headers, to limit, or prevent the content being stored and retrieved from the cache by another user:

Cache-Control: no-cache, no-store, must-revalidate, private

Pragma: no-cache

Expires: 0

This configuration directs both HTTP 1.0 and HTTP 1.1 compliant caching servers to not store the response, and to not retrieve the response (without validation) from the cache, in response to a similar request.

• https://datatracker.ietf.org/doc/html/rfc7234
• https://datatracker.ietf.org/doc/html/rfc7231
• https://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html

Validate all input and sanitize output it before writing to any HTML attributes.

• https://cheatsheetseries.owasp.org/cheatsheets/Input_Validation_Cheat_Sheet.html