Lec 2: Security Principals Flashcards
How to analyze the security of a system?
- What is the system and what is its value
- identify the attack surface
– how can it be attacked?
- identify potential vulnerabilities
- identify the threats and adversaries
– what is the threat model you need to protect against?
- triage
What is the system?
What is the attack surface? (What are the avenues by which someone might try to attack your system?)
Why use attack trees?
- to think about attack surface like a bad guy
What are vulnerabilities?
What are threats? What do they correspond to?
- Actions by adversaries who try to exploit vulnerabilities to damage asset
- Correspond to confidentiality, integrity, authenticity and availability
What are the threats to a voting machine?
- Extract records: find out who voted for who
- Tampering with data: change outcome of election
- Spoofing identity: vote as someone else
- Crash machine: prevent others from voting
What is confidentiality and how can it be violated?
What is integrity and how can it be violated?
What is authenticity and how can it be violated?
What is availability and how can it be violated?
Why do you need a threat model?
- to organize what you assume about attackers’s goals and capabilities
What do you assume about attacker’s goals and capabilities?
What is the triage?
- threats, vulnerabilities and asset value
How do you evaluate what combination of threats * vulnerabilities * asset value are the biggest?
What is the shared secret between the physical lock and key?
What is a bitting code?
- the discrete code that a key is cut with
– cuts at regular intervals (4-6 cuts)
– depth of cuts quantized in standard fashion
What are the design assumptions of a physical lock?
- if you don’t know the secret code, you can’t open the lock
- the secret code is secret
- if you can’t open the lock, everything is fine
How is the design assumption “if you don’t know the secret code, you can’t open the lock” flawed?
- lock bypass via manipulation
1. picking
2. raking
3. bumping
How does picking a lock work?
How does raking a lock work?
How does bumping a lock work?
Defenses for picking, raking, and bumping attacks?
- security pins
– Spool pins, mushroom pins, interlocking pins
—- Shapes that get “stuck” when plug under tension
—- Pin rotation (angled cuts on keys)
- ancillary locking mechanisms; sidebars
How do master keys work?
Second set of pins (spacers); multiple shear lines
