GHSA-9358-cpvx-c2qp Magento LTS's guest order "protect code" can be brute-forced too easily

• Packagist openmage/magento-lts: < 19.5.1 → fixed in 19.5.1 • Packagist openmage/magento-lts: >= 20.0.0, < 20.1.1 → fixed in 20.1.1

Impact Guest orders may be viewed without authentication using a "guest-view" cookie which contains the order's "protect_code". This code is 6 hexadecimal characters which is arguably not enough to prevent a brute-force attack. Exposing each order would require a separate brute force attack. Patches None. Workarounds Implementing rate-limiting at the web server would help mitigate the issue. In particular, a very strict rate limit (e.g. 1 per minute per IP) for the specific route (`sales/guest/view/`) would effectively mitigate the issue. References Email from Frank Rochlitzer ([email protected]) to [email protected]: Summary The German Federal Office for Information Security (BSI) found the following flaw in OpenMage through a commissioned pen test: The web application was found to accept certain requests even without prior strong authentication if the person making the request has data that is non-public but also not secret, such as easily easily guessed transaction numbers or names. Attacking entities could possibly exploit this to retrieve sensitive information using this easier-to-obtain data and by trying random numbers. Details Customers who place an order without an account can subsequently retrieve the order data or invoice data by specifying individual information. Technically, the access is realized by specifying the cookie guest-view. The value of the cookie is Base64 encoded and contains a random value and the order number. The random value consists of six characters, where these are taken from the alphabet [0-9a-f]. In the best case, i.e. when using a cryptographically secure random number generator, this corresponds to an entropy of 24 bits. Furthermore, the order numbers are assigned incrementally, so that the number range can be narrowed down or an upper limit determined by placing an order. Specifically, this results in the risk that an attacking entity can iterate over all possible values of the cookie's random value. If successful, the billing address, shipping address, payment details and the ordered items can be viewed. The attack only works for orders made as a guest. PoC The request/response pair shows the retrieval of an order. It should be noted in particular, that the cookie is not bound to a session. The response has been formatted for formatted for readability. Request: ``` 1 GET /magento19/index.php/default/sales/guest/view/ HTTP/1.1 2 Host: localhost.local 3 Cookie: guest-view=MzYyYzI4OjEwMDAwMDQzMQ%3D%3D; 4 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 5 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8 6 Accept-Language: en-US,en;q=0.5 7 Accept-Encoding: gzip, deflate 8 Referer: https://localhost.local/magento19/index.php/default/egovs_checkout/multipage/successview/ 9 Upgrade-Insecure-Requests: 1 10 Sec-Fetch-Dest: document 11 Sec-Fetch-Mode: navigate 12 Sec-Fetch-Site: same-origin 13 Sec-Fetch-User: ?1 14 Te: trailers 15 Connection: close ``` Response: ``` 1 HTTP/1.1 200 OK 2 Date: Tue, 13 Dec 2022 14:06:13 GMT 3 Server: Apache 4 Strict-Transport-Security: max-age=31536000; includeSubDomains 5 X-Powered-By: PHP/7.4.6 6 Set-Cookie: om_frontend=id7v84a05u8mm1j32t2kj5rbjl; expires=Tue, 13-Dec-2022 15:06:13 GMT; Max-Age=3600; path=/magento19/; domain=localhost.local; secure; HttpOnly 7 Expires: Thu, 19 Nov 1981 08:52:00 GMT 8 Cache-Control: no-store, no-cache, must-revalidate 9 Pragma: no-cache 10 Set-Cookie: om_frontend=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT; Max-Age=0; path=/magento19/; domain=localhost.local; secure; HttpOnly; SameSite=None 11 Set-Cookie: om_frontend=o42vttknheaj0sr3q0381jipdp; expires=Tue, 13-Dec-2022 15:06:13 GMT; Max-Age=3600; path=/magento19/; domain=localhost.local; secure; HttpOnly 12 Set-Cookie: guest-view=MzYyYzI4OjEwMDAwMDQzMQ%3D%3D; expires=Tue, 13-Dec-2022 14:16:13 GMT; Max-Age=600; path=/; domain=localhost.local; secure; HttpOnly; SameSite=None 13 X-Frame-Options: SAMEORIGIN 14 X-Content-Type-Options: nosniff 15 X-XSS-Protection: 1; mode=block 16 Referrer-Policy: same-origin 17 Feature-Policy: geolocation 'self'; vibrate 'none' 18 Content-Security-Policy: default-src 'self';script-src 'self' 'unsafe-inline' 'unsafeeval'; style-src 'self' 'unsafe-inline'; 19 Connection: close 20 Content-Type: text/html; charset=UTF-8 21 Content-Length: 47876 22 23 24 25 […] 26 27 Bestellung #100000431 - Ausstehende Überweisung 28 29 […] 30 Versandadresse 31 32 33 Herr Vorname Nachname 34 Straße 35 Dresden, Brandenburg, 01067 36 Deutschland 37 38 39 […] 40 Rechnungsadresse 41 42 43 [color]Herr Vorname Nachname 44 Straße 45 Dresden, Brandenburg, 01067 46 Deutschland[/color] 47 48 49 […] 50 Zahlungsart 51 52 53 Vorkasse 54 Bankverbindung 55 56 […] 57 58 Kassenzeichen: WS1712000349 59 60 Bestellte Artikel 61 […] 62 63 Testprodukt Kreditkarte 64 […] 65 100,23 € 66 […] 67 ``` Impact Information disclosure. Read as well as write access to sensitive information of persons or accounts and the execution of actions on their behalf must always be secured by strong authentication. This can be ensured, for example, by enforcing strong passwords or MFA. For temporary accesses to sensitive information, temporary passwords or authentication tokens or comparable data that an attacking entity cannot easily guess or determine should be used. Random values should have sufficient entropy so that searching the number space is impractical for attacking entities. Furthermore, such queries should be limited by rate limiting. The exact attack effort cannot be determined, since this requires the proportion of the proportion of orders that were placed without an account and since the performance of the performance of the production system is likely to differ from that of the test system. In a test run, 1000 requests could be made within 36 seconds. Part of the execution is shown in the screenshot. The complete search of the number space for the random value would take 6 days 23 hours 46 minutes. Accordingly, the expected value is about 3.5 days. If every third order is executed without an account, the effort must be multiplied by a factor of 3. Mit freundlichen Grüßen Frank Rochlitzer (github: theroch)