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crazylion lee

ElevenPaths/EvilFOCA - 0 views

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    "Man In The Middle (MITM) attack"
crazylion lee

My First 10 Minutes On a Server - Primer for Securing Ubuntu - 0 views

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    "My First 5 Minutes on a Server, by Bryan Kennedy, is an excellent intro into securing a server against most attacks. We have a few modifications to his approach that we wanted to document as part of our efforts of externalizing our processes and best practices. We also wanted to spend a bit more time explaining a few things that younger engineers may benefit from."
crazylion lee

Two Generals' Problem - Wikipedia - 0 views

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    "In computing, the Two Generals Problem is a thought experiment meant to illustrate the pitfalls and design challenges of attempting to coordinate an action by communicating over an unreliable link. In the experiment, two generals are only able to communicate with one another by sending a messenger through enemy territory. The experiment asks how they might reach an agreement on the time to launch an attack, while knowing that any messenger they send could be captured."
張 旭

A Tour of Rails' jQuery UJS - 0 views

  • “I should really figure out what that does someday.”
  • today is that day
  • jquery-ujs wires event handlers to eligible DOM elements to provide enhanced functionality.
  • ...11 more annotations...
  • In most cases, the eligible DOM elements are identified by HTML5 data attributes.
  • using JavaScript to progressively enhance the user experience for capable browsers without negatively impacting clients that do not support or do not enable JavaScript.
    • 張 旭
       
      讓 user 有更好體驗,但是也不影響到那些沒有 JS 支援的 user
  • jquery-ujs attaches a handler to links with the data-method attribute
  • When the link is clicked, the handler constructs an HTML form along with a hidden input that sets the _method parameter to the requested HTTP verb
  • jquery-ujs attaches a handler to links or forms with the data-confirm attribute that displays a JavaScript confirmation dialog
  • Users double click links and buttons all the time.
  • Links and buttons that have a data-disable-with attribute get a click handler that disables the element and updates the text of the button to that which was provided in the data attribute and disables the button.
    • 張 旭
       
      優雅地處理了使用者重複點擊傳送按鈕的問題。
  • If the action is performed via AJAX, the handler will re-enable the button and reset the text when the request completes.
  • Thanks to jquery-ujs and Rails’ respond_with, setting remote: true is likely the quickest way to get your Rails application making AJAX requests.
  • support both AJAX and standard requests at the same time.
  • Cross-Site Request Forgery (CSRF) is an attack wherein the attacker tricks the user into submitting a request to an application the user is likely already authenticated to.
張 旭

Building a RESTful API in a Rails application - 0 views

  • designing and implementing a REST API in an intentionally simplistic task management web application, and will cover some best practices to ensure maintainability of the code.
  • each individual request should have no context of the requests that came before it.
  • each request that modifies the database should act on one and only one row of one and only one table
  • ...10 more annotations...
  • The resource endpoints should return representations of the resource as data, usually XML or JSON.
  • POST for create, PUT for update, PATCH for upsert (update and insert).
  • an existing API should never be modified, except for critical bugfixes
  • Rather than changing existing endpoints, expose a new version
  • using unique database ids in the route chain allows users to access short routes, and simplifies resource lookup
  • while exposing internal database ids to the consumer and requiring the consumer to maintain a reference to ids on their end
  • The downfall is longer nested routes
  • require reauthentication on a per-request level
  • Devise.secure_compare helps avoid timing attacks
  • Defensive programming is a software design principle that dictates that a piece of software should be designed to continue functioning in unforeseen circumstances.
crazylion lee

pytbull - IDS/IPS Testing Framework - home - 0 views

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    "You've just set up your Intrusion Detection/Prevention System (IDS/IPS) and feel "Now I'm secure". But how can you be so sure? And how much do you trust your IDS/IPS? "
張 旭

Getting Started with Rails - Ruby on Rails Guides - 0 views

  • A controller's purpose is to receive specific requests for the application.
  • Routing decides which controller receives which requests
  • The view should just display that information
  • ...55 more annotations...
  • view templates are written in a language called ERB (Embedded Ruby) which is converted by the request cycle in Rails before being sent to the user.
  • Each action's purpose is to collect information to provide it to a view.
  • A view's purpose is to display this information in a human readable format.
  • routing file which holds entries in a special DSL (domain-specific language) that tells Rails how to connect incoming requests to controllers and actions.
  • You can create, read, update and destroy items for a resource and these operations are referred to as CRUD operations
  • A controller is simply a class that is defined to inherit from ApplicationController.
  • If not found, then it will attempt to load a template called application/new. It looks for one here because the PostsController inherits from ApplicationController
  • :formats specifies the format of template to be served in response. The default format is :html, and so Rails is looking for an HTML template.
  • :handlers, is telling us what template handlers could be used to render our template.
  • When you call form_for, you pass it an identifying object for this form. In this case, it's the symbol :post. This tells the form_for helper what this form is for.
  • that the action attribute for the form is pointing at /posts/new
  • When a form is submitted, the fields of the form are sent to Rails as parameters.
  • parameters can then be referenced inside the controller actions, typically to perform a particular task
  • params method is the object which represents the parameters (or fields) coming in from the form.
  • Active Record is smart enough to automatically map column names to model attributes,
  • Rails uses rake commands to run migrations, and it's possible to undo a migration after it's been applied to your database
  • every Rails model can be initialized with its respective attributes, which are automatically mapped to the respective database columns.
  • migration creates a method named change which will be called when you run this migration.
  • The action defined in this method is also reversible, which means Rails knows how to reverse the change made by this migration, in case you want to reverse it later
  • Migration filenames include a timestamp to ensure that they're processed in the order that they were created.
  • @post.save returns a boolean indicating whether the model was saved or not.
  • prevents an attacker from setting the model's attributes by manipulating the hash passed to the model.
  • If you want to link to an action in the same controller, you don't need to specify the :controller option, as Rails will use the current controller by default.
  • inherits from ActiveRecord::Base
  • Active Record supplies a great deal of functionality to your Rails models for free, including basic database CRUD (Create, Read, Update, Destroy) operations, data validation, as well as sophisticated search support and the ability to relate multiple models to one another.
  • Rails includes methods to help you validate the data that you send to models
  • Rails can validate a variety of conditions in a model, including the presence or uniqueness of columns, their format, and the existence of associated objects.
  • redirect_to will tell the browser to issue another request.
  • rendering is done within the same request as the form submission
  • Each request for a comment has to keep track of the post to which the comment is attached, thus the initial call to the find method of the Post model to get the post in question.
  • pluralize is a rails helper that takes a number and a string as its arguments. If the number is greater than one, the string will be automatically pluralized.
  • The render method is used so that the @post object is passed back to the new template when it is rendered.
  • The method: :patch option tells Rails that we want this form to be submitted via the PATCH HTTP method which is the HTTP method you're expected to use to update resources according to the REST protocol.
  • it accepts a hash containing the attributes that you want to update.
  • field_with_errors. You can define a css rule to make them standout
  • belongs_to :post, which sets up an Active Record association
  • creates comments as a nested resource within posts
  • call destroy on Active Record objects when you want to delete them from the database.
  • Rails allows you to use the dependent option of an association to achieve this.
  • store all external data as UTF-8
  • you're better off ensuring that all external data is UTF-8
  • use UTF-8 as the internal storage of your database
  • Rails defaults to converting data from your database into UTF-8 at the boundary.
  • :patch
  • By default forms built with the form_for helper are sent via POST
  • The :method and :'data-confirm' options are used as HTML5 attributes so that when the link is clicked, Rails will first show a confirm dialog to the user, and then submit the link with method delete. This is done via the JavaScript file jquery_ujs which is automatically included into your application's layout (app/views/layouts/application.html.erb) when you generated the application.
  • Without this file, the confirmation dialog box wouldn't appear.
  • just defines the partial template we want to render
  • As the render method iterates over the @post.comments collection, it assigns each comment to
  • a local variable named the same as the partial
  • use the authentication system
  • require and permit
  • the method is often made private to make sure it can't be called outside its intended context.
  • standard CRUD actions in each controller in the following order: index, show, new, edit, create, update and destroy.
  • must be placed before any private or protected method in the controller in order to work
張 旭

Ask HN: What are the best practises for using SSH keys? | Hacker News - 0 views

  • Make sure you use full disk encryption and never stand up from your machine without locking it, and make sure you keep your local machine patched.
  • I'm more focused on just stealing your keys from you regardless of length
  • attacks that aren't after your keys specifically, e.g. your home directory gets stolen.
  • ...19 more annotations...
  • ED25519 is more vulnerable to quantum computation than is RSA
  • best practice to be using a hardware token
  • to use a yubikey via gpg: with this method you use your gpg subkey as an ssh key
  • sit down and spend an hour thinking about your backup and recovery strategy first
  • never share a private keys between physical devices
  • allows you to revoke a single credential if you lose (control over) that device
  • If a private key ever turns up on the wrong machine, you *know* the key and both source and destination machines have been compromised.
  • centralized management of authentication/authorization
  • I have setup a VPS, disabled passwords, and setup a key with a passphrase to gain access. At this point my greatest worry is losing this private key, as that means I can't access the server.What is a reasonable way to backup my private key?
  • a mountable disk image that's encrypted
  • a system that can update/rotate your keys across all of your servers on the fly in case one is compromised or assumed to be compromised.
  • different keys for different purposes per client device
  • fall back to password plus OTP
  • relying completely on the security of your disk, against either physical or cyber.
  • It is better to use a different passphrase for each key but it is also less convenient unless you're using a password manager (personally, I'm using KeePass)
  • - RSA is pretty standard, and generally speaking is fairly secure for key lengths >=2048. RSA-2048 is the default for ssh-keygen, and is compatible with just about everything.
  • public-key authentication has somewhat unexpected side effect of preventing MITM per this security consulting firm
  • Disable passwords and only allow keys even for root with PermitRootLogin without-password
  • You should definitely use a different passphrase for keys stored on separate computers,
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    "Make sure you use full disk encryption and never stand up from your machine without locking it, and make sure you keep your local machine patched"
張 旭

Ephemeral Containers | Kubernetes - 0 views

  • a special type of container that runs temporarily in an existing Pod to accomplish user-initiated actions such as troubleshooting.
  • you cannot add a container to a Pod once it has been created. Instead, you usually delete and replace Pods in a controlled fashion using deployments.
  • you can run an ephemeral container in an existing Pod to inspect its state and run arbitrary commands.
  • ...4 more annotations...
  • Ephemeral containers differ from other containers in that they lack guarantees for resources or execution, and they will never be automatically restarted, so they are not appropriate for building applications.
  • Ephemeral containers are created using a special ephemeralcontainers handler in the API rather than by adding them directly to pod.spec, so it's not possible to add an ephemeral container using kubectl edit
  • distroless images enable you to deploy minimal container images that reduce attack surface and exposure to bugs and vulnerabilities.
  • enable process namespace sharing so you can view processes in other containers.
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    "a special type of container that runs temporarily in an existing Pod to accomplish user-initiated actions such as troubleshooting. "
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