Archive for the ‘Security’ Category

Useable Sec: Good interface design (3 Rules)

Good interface design is…
  1. Easy to recover from errors
  2. Minimal training needed for a person to use the system
  3. Relies on common interaction techniques for familiarity

Usable Sec: System Centered Design

Questions Asked in a System Centered Design Approach….

  • What can be built easily on this platform?
  • What can I create from the available tools?
  • What do I as a programmer find interesting to work on?

If you’re concerned with usability, then avoid this approach!

Usable Sec: User Centered Design

  •  User Centered Design is based upon a user’s
    • Abilities and real needs
    • Context
    • Work
    • Tasks
Golden rule of interface design: “Know The User”
Note: This and other “Usable Sec” notes are indirectly or directly from my U. Maryland “Usable Security” Coursera course

Rails: Add Authentication to Your Ruby on Rails Website in 4 Easy Steps

Step 1
In the terminal:

gem install Devise
bundle install
rails generate devise:install
rails generate devise user
rake db:migrate

Step 2
In seeds.rb:

user = User.create(email: '', password: 'password1', password_confirmation: 'password1')

Step 3
In the terminal:

rake db:seed

A route will be automatically created by the devise gem

Step 4

In _topnav.html.erb:
Add an if statement to check if the user is logged in:

if user_signed_in?


CPU Registers: an Overview

Register: a small amount of storage on the CPU; the fastest method for a CPU to access data

In the x86 instruction set, a CPU uses 8 general-purpose registers:
  1. EAX — a.k.a. the accumulator register, used for performing calculations as well as storing return values
  2. EDX — a.k.a. the data register, basically an extension of EAX
  3. ECX — a.k.a. the count register, used for looping, counts DOWNWARD not upward
  4. ESI  — a.k.a. the source index, used for reading, holds the location of the input data stream
  5. EDI  — a.k.a. the destination index, used for writing, points to the location where the result is stored
  6. EBP  — a.k.a. the base pointer, used for managing function calls and stack operations, points to the bottom of the stack unless freed up from this function by the compiler, in which case it would be an extra general purpose register
  7. ESP  — a.k.a. the stack pointer, used for managing function calls and stack operations, points to the very top of the stack
  8. EBX  — an extra register, not designed for anything specific

    Another register worth mentioning is:
  9. EIP — a.k.a. the instruction pointer, points to the current instruction that is being executed; as binary code is being executed by the CPU the EIP is updated to reflect the location where the execution is occurring

White & Black box Debuggers, Intelligent Debugging, and Dynamic Analysis

Debugging is a common task for data scientists, programmers, and security experts alike. In good ole RStudio we have a nice, simple built-in white-box debugger. For many analysis-oriented coders, the basic debugging functionality of an IDE like RStudio is all they know and it may be a surprise that debugging is a bigger, much sexier, topic. Below I define and describe key topics in debugging and dynamic analysis, as well as provide links to the most cutting edge free debuggers I use.

Dynamic Analysis: Runtime tracing of a process, usually performed using a debugger. Dynamic Analysis is critical for exploit development, fuzzer assistance, and malware inspection.

Debugger: a program that is used to test and troubleshoot other programs.Intelligent Debugger: a scriptable debugger that supports extended features such as call hooking, such as Immunity Debugger and PyDbg.

White Box Debugger: Debuggers built into IDEs and other dev platforms, which enable developers to trace through source code with a high degree of control, as to aide in the troubleshooting of functions and other code breakages.
Black Box Debugger: Used by bug hunters and reverse engineers, black box debuggers operate on compiled programs when the source code is not available and the only information is available in a disassembled format. There are two broad subclasses of black box debuggers, which are user mode (i.e. ring 3) and kernel mode (i.e. ring 0).
User mode black box debugger: a processor mode under which your applications run, usually with the least amount of privilege (e.g. double clicking PuTTY.exe launches a user-mode process).
Kernel mode black box debugger: a processor mode where the core of the OS runs using the highest amount of privilege (e.g. capturing packets with a network adapter that is in passive mode).
User-mode Debuggers Commonly used among Reverse Engineers
WinDbg by Microsoft
OllyDbg by Oleh Yuschuk, a F.O.S.S. debugger
GNU Debugger (gdb), a F.O.S.S. Linux debugger by the community

Encryption in my 2nd MS Thesis


Protected: Hacker Dojo Timeline/Summary

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SQL: Use of @ to Avoid SQLInjection

The @ (i.e. @Something) means it’s a parameter that you will supply a value for later in your code. This is the best way of protecting against SQL injection.
Create your query using parameters, rather than concatenating strings and variables.
The database engine puts the parameter value into where the placeholder is, and there is zero chance for SQL injection.

Quick Tip: Shred a Directory in 1 Line

find directory -type f | xargs shred –remove
normal (recursive) directory removal:
rm -rf directory