Exam CAS-003 topic 1 question 61 discussion

B. NX/XN bit. It's purpose is to segregate memory areas used for processor instruction and data storage. ASLR was implemented in 2003. No special hardware is needed for it today. Question implies that they had to buy the correct hardware. Only processors of the Harvard architecture had the NX bit option, now processors of the von Neumann are adopting NX. NX is the term for ARM, it's XD for Intel, and EVP for AMD.

Address space layout randomization (ASLR) is a technique that is used to increase the difficulty of performing a buffer overflow attack that requires the attacker to know the location of an executable in memory.

keyword = embedded environment - NX bit

It's B

B. NX/XN bit. This has to be included for the already procured hardware to properly operate. From Wikipedia: An operating system with support for the NX bit may mark certain areas of memory as non-executable. The processor will then refuse to execute any code residing in these areas of memory. Used to prevent certain types of malicious software from taking over computers by inserting their code into another program's data storage area and running their own code from within this section; one class of such attacks is known as the buffer overflow attack.

B is correct

C. ASLR - Address space layout randomization (ASLR) is a computer security technique involved in preventing exploitation of memory corruption vulnerabilities. In order to prevent an attacker from reliably jumping to, for example, a particular exploited function in memory, ASLR randomly arranges the address space positions of key data areas of a process, including the base of the executable and the positions of the stack, heap and libraries.