Understanding Web Application Integrity

Web application integrity refers to the state where the application and its data are accurate, complete, and protected from unauthorized modification or destruction. Ensuring integrity is a crucial part of web security.

In this question, we are given two key probabilities related to potential attacks and the application's defense capabilities:

• Threat Probability: This is the estimated likelihood that an attack against the web application will occur. A higher threat probability means it's more likely the application will face an attack attempt.
• Likelihood of Repelling an Attack: This is the estimated probability that the application's security measures will successfully prevent an attack from compromising its integrity, assuming an attack occurs.

We need to calculate the overall integrity, which represents the probability that the application remains uncompromised.

Calculating Web Application Integrity

The integrity of the web application can be calculated by considering two scenarios where the application's integrity is maintained:

1. The first scenario is when no attack occurs. The probability of this happening is $1 - \text{Threat Probability}$.
2. The second scenario is when an attack does occur, but the application successfully repels it. The probability of an attack occurring is $\text{Threat Probability}$, and the probability of repelling it, given an attack, is $\text{Likelihood of Repelling}$. The probability of both happening is $\text{Threat Probability} \times \text{Likelihood of Repelling}$.

Since these two scenarios (no attack, or attack repelled) are mutually exclusive ways for the application to maintain integrity, we can sum their probabilities to find the overall integrity probability.

The formula for web application integrity in this context is:

$\text{Integrity} = (1 - \text{Threat Probability}) + (\text{Threat Probability} \times \text{Likelihood of Repelling})$

Step-by-Step Integrity Calculation

Let's use the values provided in the question to calculate the web application integrity.

• Threat Probability = 25 percent = 0.25
• Likelihood of Repelling an Attack = 30 percent = 0.30

Now, substitute these values into the formula:

$\text{Integrity} = (1 - 0.25) + (0.25 \times 0.30)$

First, calculate the probability of no threat:

$1 - 0.25 = 0.75$

Next, calculate the probability of a threat occurring AND being repelled:

$0.25 \times 0.30 = 0.075$

Finally, add these two probabilities together to find the total integrity:

$\text{Integrity} = 0.75 + 0.075 = 0.825$

Therefore, the integrity of the web application is 0.825.

Revision Table: Key Web Application Integrity Terms

Additional Information on Web Application Security

Web application security involves protecting web applications from various threats that exploit vulnerabilities. Integrity is one of the core principles, often discussed alongside Confidentiality and Availability (forming the CIA Triad).

• Confidentiality: Protecting sensitive information from unauthorized disclosure.
• Integrity: Ensuring data and systems are accurate and protected from unauthorized modification.
• Availability: Ensuring the system and data are accessible to authorized users when needed.

Improving the likelihood of repelling an attack ($0.30$ in this case) involves implementing security measures like input validation, authentication, authorization, regular security testing, patching vulnerabilities, and using firewalls or intrusion prevention systems. While this application doesn't contain sensitive data (reducing the impact if compromised), maintaining high integrity is still vital for its reliable operation.