\question\textbf{Risks in Electronic Payment:}\hfill
From your personal experience: Which risks are involved in electronic payment systems?
Start with thinking about the vulnerabilities of today’s methods, procedures, and mechanisms you are familiar with. Here are two possible scenarios:
\begin{parts}
\part Paying with a debit card (e.g. EC Maestro): starting with its use in a shop and ending with the money withdrawal from your bank account.
\part Home banking using a static (e.g. snail-mailed) or dynamically generated transaction authentication number (TAN), e.g. sent from your bank via SMS (mTAN) or using a smartphone app (pushTAN).
\end{parts}
What are the advantages of smart cards (such as your thoska), carrying a microprocessor for cryptographic computations?
Electronic payment involves theft of data or money. Hackers may get access to bank accounts and use it the same way as the normal user but with different intentions (get rich). To prevent hacking of accounts, banks use different ways of defense.
While paying with a debit card, the user must provide the card (physical item) and the pin code (knowledge). To prevent bruteforce attacks, a bank account is locked after a short number of invalid pin codes.
Home banking uses a password (knowledge) and a TAN via Mail/Phone to have the possibility of hackers minimized.
Which vulnerabilities are exploited by a buffer overflow attack? How can you counter buffer overflow attacks? How could you at least mitigate the effects of successful buffer overflow attacks?
Buffer overflow attacks aim to trick the softwar to execute futher attack code and exploit whatever the hacker needs. To prevent buffer overflow, one must check the maximum possible length of the input versus the users input. To mitigate any successfull attack, a programm should be contained and not have access to further information or programms but the necessary.
Similar to HRU, an NI model is basically formalized through a deterministic automaton. Can we also use it to analyze HRU Safety (no matter if by proof or by simulation)?
If yes: How would HRU Safety for NI be defined (in prose)? If no: What extension of the NI model in the lecture would be required to enable Safety analysis?
As with any AC model, the formal components of RBAC are designed to enable access control decisions. However, in the ACF definition of RBAC0 (which is the basis for ACFs of the other RBAC96 models), the component UA is not included. Why?
How do we model a read operation, such as for a Unix-OS file system, in HRU? Remember that this operation neither modifies the subject set, nor the object set, nor the ACM.
