Security Concepts

Question 1

Explanation

Cross site scripting (also known as XSS) occurs when a web application gathers malicious data from a user. The data is usually gathered in the form of a hyperlink which contains malicious content within it. The user will most likely click on this link from another website, instant message, or simply just reading a web board or email message.

Usually the attacker will encode the malicious portion of the link to the site in HEX (or other encoding methods) so the request is less suspicious looking to the user when clicked on.

For example the code below is written in hex:

<a href=&#x6A&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3A&#x61&#x6C&#x65&#x72&#x74&#x28&#x27&#x58&#x53&#x53&#x27&#x29>Click Here</a>

is equivalent to:

<a href=javascript:alert('XSS')>Click Here</a>

Note: In the format “&#xhhhh“, hhhh is the code point in hexadecimal form.

Question 2

Question 4

Explanation

Phishing attacks are the practice of sending fraudulent communications that appear to come from a reputable source. It is usually done through email. The goal is to steal sensitive data like credit card and login information, or to install malware on the victim’s machine.

Question 5

Question 6

Explanation

Ping of Death (PoD) is a type of Denial of Service (DoS) attack in which an attacker attempts to crash, destabilize, or freeze the targeted computer or service by sending malformed or oversized packets using a simple ping command.

A correctly-formed ping packet is typically 56 bytes in size, or 64 bytes when the ICMP header is considered, and 84 including Internet Protocol version 4 header. However, any IPv4 packet (including pings) may be as large as 65,535 bytes. Some computer systems were never designed to properly handle a ping packet larger than the maximum packet size because it violates the Internet Protocol documented

Like other large but well-formed packets, a ping of death is fragmented into groups of 8 octets before transmission. However, when the target computer reassembles the malformed packet, a buffer overflow can occur, causing a system crash and potentially allowing the injection of malicious code.

Question 7

Explanation

Understand how your framework prevents XSS and where it has gaps. There will be times where you need to do something outside the protection provided by your framework. This is where Output Encoding and HTML Sanitization are critical -> Answer B is correct.

For XSS attacks to be successful, an attacker needs to insert and execute malicious content in a webpage. Each variable in a web application needs to be protected. Ensuring that all variables go through validation and are then escaped or sanitized is known as perfect injection resistance. Any variable that does not go through this process is a potential weakness. Frameworks make it easy to ensure variables are correctly validated and escaped or sanitised.

However, frameworks aren’t perfect and security gaps still exist in popular frameworks like React and Angular. Output Encoding and HTML Sanitization help address those gaps -> Answer D is correct.

Reference: https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.md

Question 8

Explanation

In deceptive phishing, fraudsters impersonate a legitimate company in an attempt to steal people’s personal data or login credentials. Those emails frequently use threats and a sense of urgency to scare users into doing what the attackers want.

Spear phishing is carefully designed to get a single recipient to respond. Criminals select an individual target within an organization, using social media and other public information – and craft a fake email tailored for that person.

Question 9

Explanation

A buffer overflow (or buffer overrun) occurs when the volume of data exceeds the storage capacity of the memory buffer. As a result, the program attempting to write the data to the buffer overwrites adjacent memory locations.

Buffer overflow is a vulnerability in low level codes of C and C++. An attacker can cause the program to crash, make data corrupt, steal some private information or run his/her own code. It basically means to access any buffer outside of it’s alloted memory space. This happens quite frequently in the case of arrays.

Question 10

Explanation

TAXII (Trusted Automated Exchange of Indicator Information) is a standard that provides a transport mechanism (data exchange) of cyber threat intelligence information in STIX (Structured Threat Information eXpression) format. In other words, TAXII servers can be used to author and exchange STIX documents among participants.

STIX (Structured Threat Information eXpression) is a standardized language which has been developed in a collaborative way in order to represent structured information about cyber threats. It has been developed so it can be shared, stored, and otherwise used in a consistent manner that facilitates automation and human assisted analysis.

Question 11

Explanation

The Trusted Automated eXchangeof Indicator Information (TAXII) specifies mechanisms for exchanging structured cyber threat information between parties over the network.

TAXII exists to provide specific capabilities to those interested in sharing structured cyber threat information. TAXII Capabilities are the highest level at which TAXII actions can be described. There are three capabilities that this version of TAXII supports: push messaging, pull messaging, and discovery.

Discovery does, however, allow for the automated exchange of information about which TAXII Capabilities a Producer might support and the technical mechanisms they employ in doing so -> Therefore the best alternative word for “Discovery” is “Exchange”.

Reference: https://docs.oasis-open.org/cti/taxii/v1.1.1/taxii-v1.1.1-part1-overview.html