--Originally published at Mental Droppings of a Tired Student

A security model is a specification of a security policy it describes the entities governed by the policy, it states the rules that constitute the policy.

There are various types of security models:

• Models can capture policies for confidentiality or for integrity.
• Some models apply to environments with static policies, others consider dynamic changes of access rights.
• Security models can be informal, semi-formal, or formal.

Model vs Policy

A security model maps the abstract goals of the policy to information system terms by specifying explicit data structures and techniques that are necessary to enforce the security policy. A security model is usually represented in mathematics and analytical ideas, which are then mapped to system specifications, and then developed by programmers through programming code.

For Example, if a security policy states that subjects need to be authorized to access objects, the security model would provide the mathematical relationships and formulas explaining how x can access y only through the outlined specific methods
A security policy outlines goals without regard to how they will be accomplished. A model is a framework that gives the policy form and solves security access problems for particular situations.

Read more about secuirty policies in my next post.

Here are three classic security architecture models:

Lattice Models

• A lattice is a mathematical construct that is built upon the notion of a group.
• A lattice is a mathematical construction with:
  • a set of elements
  • a partial ordering relation
  • The property that any two elements must have unique least upper bound and greatest lower bound

A security lattice model combines multilevel and multilateral security Lattice elements are security labels that consist of a security level and set of categories.

State Machine Models

In state machine model, the state of a machine is captured in order to verify the security

--Originally published at Mental Droppings of a Tired Student

In all types of engineering, sophisticated risk assessments are often used  within companies when it concerns threats to life, environment or machine functioning. The nuclear, aerospace, oil, rail and military industries have a long history of dealing with risk assessment. Medical, hospital, social service and food industries control risks and perform risk assessments on a continual basis. Methods for assessment of risk may differ between industries and whether it pertains to general financial decisions or environmental, ecological, or public health risk assessment.

Risk assessment is the determination of quantitative or qualitative estimate of risk related to a well-defined situation and a recognized threat. Quantitative risk assessment requires calculations of two components of risk:

• The magnitude of the potential loss (L)
• The probability (p) that the loss will occur.

An acceptable risk is a risk that is understood and tolerated usually because the cost or difficulty of implementing an effective countermeasure for the associated vulnerability exceeds the expectation of loss.

Part of the difficulty in risk management is that both the quantities by which risk assessment is concerned (potential loss and probability of occurrence) can be very difficult to measure. The chance of error in measuring these two concepts is high.

The following methodologies that are commonly used by security
practitioners and consultants for risk assessment:

• Asset Audit
•  Pipeline Model
•  Attack Tree

Asset Audit

The asset audit approach is an easy-to-use and straightforward method for
assessing risks by giving the reviewer and owners a direct approach of looking at
all the information assets and their risk exposure. The people involved in the
asset audit process also obtain a better understanding of how information flows
in and out of, as well as, is stored on the system. With this knowledge and insight
of the system and the information flow, the reviewer can have

--Originally published at TC2027 – Will It Blog?

A network is done when two or more machines are connected together and sharing resources. The internet is not more than a network of networks. Right now I’m going to focus in wired networks security. The wire used to connect two computers using the Ethernet protocol is called UTP (Unshielded Twisted Pair). This commonly are connected to switches which are connected to Routers, this is the basic scheme of a network.

Also neat network wiring looks really awesome, just like the armor of an Eva Unit.

Back to the topic, common vulnerability is  unauthorized access, which well the term explain itself. If the attacker gains access it can exploits several vulnerabilities. Tthe following are a list of vulnerabilities found in several of the parts that conform a network. I will require that you already know what the Layers of the OSI Model are and what sort of protocols are used at each level (I will leave a diagram just in case).

Vulnerabilities inside TCP/IP Protocol

This is the protocol suite (group of protocols) in which the internet is builded on. One of the protocols that runs in this model is the TCP protocol which has a vulnerability in the three way handshake done when establishing a new connection, an attacker can open a half open session through tons of SYN messages, this would eventually flood the server and make it crash, also IP spoofing attacks can be done through the network (like the ping of death) used in DoS attacks.

Vulnerabilities in the DNS

The Domain Name Server the one in charge of resolving host names into ip addresses also has vulnerabilities that could be exploited. This program can be attacked to modify its records and redirect traffic to an incorrect or malicious IP address, this goes by the name

--Originally published at TC2027 – Will It Blog?

Through this semester one of my goals was to learn php and hopefully understand how the backed of an application worked, it also resulted convenient because I had a course on Web development and I though I would be using it on my project for that class.

But at the end I heard from colleagues and forums how it was a pretty unruly/insecure language and through the course we once used this framework called CakePHP. That was my first approach ever to MVC arquitechture. I didn’t like it, it was confusing and it was after watching 2 tutorials that I started understanding what was going on. There are also other php frameworks like lavarel that offer a more elegant way of writing code but I think the thing is that one must understand or have an idea of the language the framework is using.

So I started reading this guide of crude php and what surprised me the most was this part mentioned when covering the part of sessions inside php.

Session fixation describes an attack vector in which a malicious third-party sets (i.e. fixes) the session identifier (SID) of a user, and is thus able to access that user’s session.

And they proceed to mention other things like not to store sensitive information on a cookie, md5 hashing (to “increase” security on data exchange) and other stuff, but I was still worried about the security involved when using this language. What I want to cover is the vulnerabilities that the language has and what I think is the reason that it is so rejected by many developers.

First of all php comes as a language of back end (server side oriented), created back in 1994 and its meaning was PERLsonal home page as I will call it

--Originally published at TC2027 – Will It Blog?

It is a fact that system administrators may found themselves also doing some security tasks within their organizations or projects, having to carry  on the security of both users (technical aspects) and upper management (explain costs).

What is risk analysis?

This is procedure is used to estimate potential losses that may result from system vulnerabilities and to quantify the damage of those. So as a  primary goal of risk analysis we have the selection of cost-effective safeguards to reduce risk to an acceptable level.

In more simple words,  is a way to figure out how important is your system and how far you are willing to go to protect it.

First we want to detect the most valuable asset (information and puppies) aside from the tangible assets (equipment). Also consider the importance and vulnerability of that information.Costs. The cost of losing or compromising the information and the cost of protecting the information (maintenance)

Contingency plan

Plan for disaster, it may spell the difference between a problem and a catastrophe.Backups are the key to disaster planning. As simple as invoking activities as backing up data for storage at remote secure facilities and arranging other equipment facilities.

Thread Modeling

Getting into more technical stuff one of the first steps into any kind of security developing life cycle model is threat modeling therefore is a procedure that optimizes any kind of app or network instance by identifying objectives and vulnerabilities, and then countermeasures to prevent or mitigate its effect.

The image below (courtesy of Microsoft) are the steps of a generic threat modeling process

Once done, the next thing you want to do is to find security issues by performing several code reviews or penetration tests, otherwise the problems will not be discovered until production time and that just compromises the