What is TLS fallback?
TLS_FALLBACK_SCSV is a TLS Signaling Cipher Suite Value (SCSV) that can be used to guard against protocol downgrade attacks. The extension can be useful for clients like web browsers, which fall back to a lesser protocol version if attempts to use a higher protocol version fail.
What is TLS client and server?
TLS is a connection-oriented protocol that provides a secure channel between a client and a server. The TLS handshake protocol provides a means for authentication and the negotiation of security parameters, such as the encryption algorithms, encryption keys, MAC keys, etc., that are used to transmit data securely.
What happens if my server does not support TLS FALLBACK SCSV?
Basically, if your server does not support TLS_FALLBACK_SCSV, then active attackers will be able to force a downgrade, even if the client would have supported TLS_FALLBACK_SCSV.
Which is the default security.tls.version.fallback?
Hi folks, I have a question about this combination in config: security.tls.version.fallback-limit = 3 security.tls.version.max = 3 security.tls.version.min = 1 All of those are default in FF 48.0.2 . According to KB, FF should allow TLS 1.0, 1.1 and 1.2, and fallback is not allowed from TLS 1.2.
Why do I need to enable TLS fall back?
If disabled and the TLS negotiation produces a weaker protocol, an attacker may have eavesdropped on the connection and changed the request in a way, that he can break the encryption due to a weak protocol. Follow this guide to enable TLS_FALLBACK_SCSV:
Is it possible to downgrade to TLS 1.2?
E.g. client and server can support all versions from SSL 3.0 to TLS 1.2 (TLS 1.2 is, internally, “SSL 3.3”), and attackers cannot force a downgrade because even the SSL 3.0 handshake is robust enough not to be immediately broken by active attackers — and that handshake includes the advertised maximum version.