A Linux system allows SSH login using deprecated ciphers.

The correct answer is C because allowing deprecated SSH ciphers creates a cryptographic weakness that can expose the system to downgrade-style attacks. SSH is intended to provide secure remote administration over TCP port 22 and relies on cryptographic protection for confidentiality and secure communication. CEH secure communication topics describe SSH as a secured alternative to Telnet using public-key cryptography for encryption. When obsolete or weak ciphers remain enabled, an attacker positioned in the communication path may try to influence negotiation so that the client and server use a weaker encryption option instead of a stronger one. CEH cryptography attack examples such as FREAK and POODLE show the same principle: attackers abuse fallback or weak algorithm support to force communication toward weaker encryption. This does not directly indicate DoS, XSS, or SQL injection. The primary risk from deprecated SSH ciphers is weakened encrypted communication and possible downgrade attacks.