Transmits credentials in plaintext.
Susceptible to credential sniffing and session hijacking.
Lacks encryption by default unless configured for POP3S.
Use POP3S (SSL/TLS) to secure communication.
Enforce strong password policies.
Monitor POP3 access logs for unusual patterns.
Unencrypted traffic on port 110 (TCP).
Repeated failed login attempts.
Abnormal POP3 traffic volumes.