quartz/content/notes/19-security.md

title	aliases	tags	sr-due	sr-interval	sr-ease
19-security		cosc202 lecture	2022-05-16	3	250

• why cybersecurity is a growing concern
• sketch confidentiality, integrity, and avalability security
• appreciate that dependencies cause security risks
• explain risks from non-validation of user input
• outline how injection attack works

growing problem

• more software around
• more dependencies
  • resuse of old code rather than starting from scratch
• more complex programs
• "surface area" of risk is growing
• speed of development has trumped security
• some languages are inherently more secure than other
  • e.g., C can access any memory
• software systems involve large numbers of components
  • large amounts of code is almost guaranteed to have bugs

Security in development

• • security isn't a single requiremtn you can tick off
    • it needs consideration throughtout the whole system
    • it is a cross-cutting concern
    • it is hard to retrofit
• notion of security engineering is useful
  • affects design descision fromt the outset
  • changes how code is written and reviewed
  • add a specific type of testing to include
  • needs examination of how users interact with software

Threat model

• should character what you want to protect against
• writin standalone software to be used by one person
  • typially dont have to worry about malicious attacks (on self)
• software on a multi-user operating system
  • do need to think about cross-user data leaks
  • all OSs are multi user
• software that has network availability
  • your software can and likely will be attacked
• targeteted by state-sponsored teams? Good Luck...

Divide into three areas

• confidentiality - e.g., sensitive data is not visible
• integrity e.g., data is protected from modification
• avaliability e.g., services stay accessible

Confidentiality

• attacks on this involve stealing data
• protect using encrytion (unsecured network or disk) or isolation of processes (if you trust the OS)
• encrption does not necessarly work forever.

Integrity

• attacks on data may aim to decieve users
• defence: apply checksums (e.g., check secure hash of data)
• attacks on code are often for privilege esccalation
  • e.g., attacker moves from normal user to super user
  • defence: avoid decisions being influenced by outside sources

Availability

• e.g., DDoS
  • ditributed denial of service
• Defence: host services in multiple countries
  • use CDNs (content delivery networks) for data objects

Key soft. dev. security area 1: dependencies

• vulnerabilities in dependencies affect your code too

  • determine and examine your software bill of materials SBOM

• subscribe to security alerts for your key dependencies

  • plan to rapidly rebuild and release you software at short notice

• use tools to scan software for know problems

  • e.g., gitlab auto devOps scancs containers for vulnerabilites

• doesn't mean dont use them

  • use them if they are good

• e.g.,

  • dont implement crypto yourself
  • use a secret manager for authentication
  • XACML libray
  • use libraries to parse data

Key soft. dev. security area 1: santise input

• treat user controlled inpuut to your code as malicious
  • databases must prevent SQL injection
• many input sources
  • user docs
  • config files
  • env variables

Injection attacks

• rough def$^n$ some structure is not contained properly
• 

Resolving problems