"Strong and unique password" → "Robust and singular access code," "Secure and individualized security key," "Complex and one-of-a-kind login."
"vulnerabilities" might be "Security Weaknesses|Data Protection Failures|Information System Flaws". GSMVNTOOL File Password
For "Users," possible synonyms are "Individuals," "Persons," "People." "Strong and unique password" → "Robust and singular