Week 10 - Software security

Which of the following(s) describes Command Injection

• Exploiting the vulnerability of accepting unexpected user input

• inserting new malicious code into a vulnerable application, which executes

• Executing arbitrary commands in a system shell or other parts of the environment

• To override original command, gain access to a system, obtain sensitive data

Answer explanation

Wrong option: Refers to code injection, not command injection

Code injection focuses on injecting code into a vulnerable application, not system

Buffer overflow: A condition at an interface under which more input can be placed into a buffer or data holding area than the capacity allocated, overwriting other information. This holding area for the buffer is known as a ... ?

(a)  

Which of the followings are techniques used in Good Programming practices to prevent command injection?

• Secure programming - nothing is assumed

• Use safe APIs instead of unsafe APIs

• Proper input validation (black/whitelist)

• Enable CORs to prevent malicious codes accessing unauthorized memory

strcpy(dest, src) is considered unsafe compared to its counterpart strncpy(dest, src, num). What does the parameter 'num' do?

• It ensures that the char length is equal or smaller than num

• It ensures that the char length is equal to num

• It ensures that the char length is larger than num

• It ensures that the address is num

Answer explanation

It ensures that the input does not overflow, thus making sure the char is equal or smaller than num

Buffer overflow Counter measure: System supports

Which of the following are system support techniques

• Immutable code and inexecutable data in the memory

• Use memory safe languages

• Address randomization when program is launched

• Control flow integrity enforcements

Which system supports does this:

The OS has an ACL-like approach to specify whether bytes in a memory region can be read, written or executed

• Immutable code and inexecutable data in the memory

• Address randomization when a program is launched

• Control flow integrity enforcement

• Discretionary Access Control

Memory safe languages have bult-in defense against memory errors because they have inbuilt interpreters. Which languages are NOT memory safe

• C#

• C++

• C

• Rust

Which type of malware(s) have the following properties:

Non-replicating

Parasitic

• Virus

• Trojan horse

• Time bomb

• Logic bomb

Which type of malware(s) have the following properties:

Self-contained

• Worm

• Bot

• Virus

• Logic bomb

Malware have many ways to conceal themself. Which of the following malware that has these traits:

- Encrypt itself

- Change its code

- Core behavior remains the same

• Metamorphic virus

• Polymorphic virus

• Encrypted virus

• Endomorphic virus