S
Safe Mode
SAML
Scareware - fake virus alerts, telltale signs, and how to avoid them
Screened Subnet (DMZ) Firewall
SECaaS
Security Software
Session Hijacking
SHA-1
Shadow Copy
Shadow Password Files
SIEM
Signature
Smishing
Social Engineering
Spam
Spoofing
Spyware
SQL Injection (SQLi)
Steganalysis
Stream