CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Disable TLS 1.0 and 1.1 on the server

  Why this is correct

  Disabling specific older TLS versions like 1.0 and 1.1 on the server directly removes the server's capability to negotiate these protocols. If the server does not support or offer these versions, an attacker cannot force a client and server to communicate using them, thereby eliminating the target for a downgrade attack. This is a fundamental server-side configuration best practice for security.

• ✓

  Use the TLS_FALLBACK_SCSV cipher suite

  Why this is correct

  The TLS_FALLBACK_SCSV (Signaling Cipher Suite Value) cipher suite is a client-side mechanism designed to prevent downgrade attacks. When a client attempts to reconnect using a lower TLS version after a previous failed attempt with a higher version, SCSV signals this potential downgrade to the server. The server, upon receiving this signal, can then abort the connection, effectively thwarting the attacker's attempt to force an older, less secure protocol.

• ✗

  Use self-signed certificates to avoid CA trust issues

  Why it's wrong here

  Using self-signed certificates does not prevent TLS version downgrade attacks; their primary function is to establish identity, not to enforce protocol versions. While they can avoid reliance on commercial Certificate Authorities, they introduce significant trust issues as clients must explicitly trust them, often leading to security warnings or manual trust additions. Improper validation of self-signed certificates can actually facilitate Man-in-the-Middle attacks rather than prevent them.

• ✓

  Enforce a minimum TLS version of 1.2 in server configuration

  Why this is correct

  Enforcing a minimum TLS version of 1.2 in the server configuration ensures that the server will only accept connection attempts that propose TLS 1.2 or higher. Any client attempting to negotiate an older, less secure protocol version, such as TLS 1.0 or 1.1, will have its connection attempt rejected by the server. This policy-driven approach directly prevents downgrade attacks by eliminating the server's willingness to communicate via vulnerable legacy protocols.

• ✗

  Disable all cipher suites except those using RC4

  Why it's wrong here

  Disabling all cipher suites except those using RC4 is a highly insecure practice and does not prevent TLS version downgrade attacks. RC4 is a stream cipher known to be cryptographically weak and susceptible to various attacks, including biases in its keystream. Furthermore, cipher suite selection operates within a negotiated TLS version; a downgrade attack specifically targets the *protocol version* itself, forcing the use of an older, vulnerable protocol like TLS 1.0 or SSLv3, regardless of the cipher suites available within that version.

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