FREAK
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| Fiche express | |
|---|---|
| CVE | CVE-2015-0204 |
| Type | Downgrade TLS / MITM |
| Nom | Factoring attack on RSA-EXPORT Keys |
| Cause | Acceptation de cles RSA export 512 bits |
FREAK (Factoring attack on RSA-EXPORT Keys, CVE-2015-0204) est une attaque de type MITM contre TLS. Elle force le client a negocier une suite RSA export a cle faible (512 bits), que l'attaquant peut factoriser pour dechiffrer l'echange. Elle touche de nombreux clients Windows, Android, Apple et BlackBerry.
FREAK
- FREAK -> Factoring Attack on RSA-EXPORT Keys
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0204
FREAK est similaire a POODLE puisque qu'il permet de casser la protection openssl via un MITM. Il
touche tous les windows ainsi que les android, apple et blackberry.
Il force les clients a utiliser l'encryption la moins forte (512-bit).
http://blog.cryptographyengineering.com/2015/03/attack-of-week-freak-or-factoring-nsa.html
deroulé
- In the client's Hello message, it asks for a standard 'RSA' ciphersuite.
- The MITM attacker changes this message to ask for 'export RSA'.
- The server responds with a 512-bit export RSA key, signed with its long-term key.
- The client accepts this weak key due to the OpenSSL/Secure Transport bug.
- The attacker factors the RSA modulus to recover the corresponding RSA decryption key.
- When the client encrypts the 'pre-master secret' to the server, the attacker can now decrypt it to
- recover the TLS 'master secret'.
- From here on out, the attacker sees plain text and can inject anything it wants.
-> TLS_RSA_EXPORT_WITH_DES40_CBC_SHA
- tester sa vulnérabilité :
https://tools.keycdn.com/freak