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What Does Your User Agent Say About You?

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A user agent is a computer program representing a person, for example, a browser in a Web context.

Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.

Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.

The user agent string can be accessed with JavaScript on the client side using the navigator.userAgent property.

A typical user agent string looks like this: "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0".

(Source: Mozilla.org)

User Agent String

Browser Data

User Agent Oauth

author
Danielle Fletcher
• Tuesday, 06 October, 2020
• 21 min read

The user agent application is used by the client applications in the user's device, which acts as the scripting language instance such as JavaScript running in a browser. You can store the user agent application on a web server.

oauth flow flows agent general salesforce
(Source: cloudsundial.com)

Contents

The following diagram shows the architecture of the client user agent application. We can store the user agent application which is done on the web server.

The following diagram shows the architecture of the public client user agent application. Then, the public client user agent application provides an instance of a JavaScript application running in a browser and links to the web hosting client.

It’s also used by public client apps running in a browser using a scripting language such as JavaScript. In this diagram, the user ’s credentials are used by the application to request an access token The application uses the user username and password to request an access token.

This is done through an out-of-band POST request to the appropriate Salesforce token request endpoint, Salesforce verifies the user credentials, and if it is successful, it sends a response to the application with the access token. Access tokens have a limited lifetime which is specified by the session timeout in Salesforce.

You may need to change certain settings such as trusted and restricted IP ranges to enable access to the org from your IP address. Ensure that the URL doesn’t redirect to other website.

oauth user token server flow authentication flows authorization access gateway api agent resource oracle obtaining identify docs doc cd
(Source: docs.oracle.com)

In this URL, replace the {{ConnApp_ConsumerKey}} and {{ConnApp_CallbackURL}} variables with the actual Consumer Key and Callback URL of your connected app, for example: Open the downloaded response.html file in a web browser.

When prompted, enter your Salesforce username and password and allow access for your connected app: This is authorization code for your connected app.

User logs in to authorization end point and does not interact with client application at all. Redirect is sent back to users browser appended with authorization code.

Client application extracts the access code and sends to authorization end point. If successful authorization end point returns access and refresh tokens.

Flow is used for authentication for client applications that reside on users' device. Key difference with web server flow is that client cannot keep consumer secret confidential.

clients oauth wso2 docs authorization typically grant code type these
(Source: docs.wso2.com)

User logs in to authorization end point and does not interact with client application at all 3. Redirect is sent back to users browser appended with access token 4.

The flow is discouraged due to username and password being used back and forth in requests. To begin at a high level, OAuth is not an API or a service: it’s an open standard for authorization and anyone can implement it.

More specifically, OAuth is a standard that apps can use to provide client applications with “secure delegated access.” OAuth works over HTTPS and authorizes devices, APIs, servers, and applications with access tokens rather than credentials. OAuth was created as a response to the direct authentication pattern.

This pattern was made famous by HTTP Basic Authentication, where the user is prompted for a username and password. Basic Authentication is still used as a primitive form of API authentication for server-side applications: instead of sending a username and password to the server with each request, the user sends an API key ID and secret.

Before OAuth, sites would prompt you to enter your username and password directly into a form, and they would log in to your data (e.g. your Gmail account) as you. In this scenario, an end user talks to their identity provider, and the identity provider generates a cryptographically signed token which it hands off to the application to authenticate the user.

identity server
(Source: medium.com)

As long as that trust relationship works with the signed assertion, you’re good to go. The diagram below (from OKTA’s OAuth docs) shows how this works.

Federated identity was made famous by SAML 2.0, an OASIS Standard released on March 15, 2005. It’s a large spec but the main two components are its authentication request protocol (a.k.a.

Web SSO) and the way it packages identity attributes and signs them, called SAML assertions. SAML is basically a session cookie in your browser that gives you access to web apps.

It’s limited in the kinds of device profiles and scenarios you might want to do outside a web browser. Now we have modern web and native application development platforms.

There are Single Page Applications (Spas) like Gmail/Google Inbox, Facebook, and Twitter. They have different behaviors than your traditional web application because they make AJAX (background HTTP calls) to APIs.

oauth flow protocol process diagram framework configuring bmc following authorization performs docs tasks
(Source: docs.bmc.com)

Mobile phones make API calls too, as do TVs, gaming consoles, and IoT devices. REST is, in a nutshell, HTTP commands pushing JSON packets over the network.

The API Economy is a common buzzword you might hear in boardrooms today. Companies need to protect their REST APIs in a way that allows many devices to access them.

It decouples authentication from authorization and supports multiple use cases addressing different device capabilities. After authenticating and obtaining the key card, you can access resources across the hotel.

App presents proof of authorization to server to get a Token. Token is restricted to only access what the User authorized for the specific App.

Scopes and Consent Actors Clients Tokens Authorization Server Flows Scopes are what you see on the authorization screens when an app requests permissions.

(Source: forum.bubble.io)

They’re bundles of permissions asked for by the client when requesting a token. Scopes decouple authorization policy decisions from enforcement.

They’re often listed in the API docs: here are the scopes that this app requires. It’s a pretty significant user experience change on the web.

There are all kinds of users from the tech-savvy young folk to grandparents that aren’t familiar with this flow. It can be a time-sensitive range (day, weeks, months), but not all platforms allow you to choose the duration.

Resource Server : The API which stores data the application wants to access. They’re running in a protected area where end users can’t access them.

Public clients are browsers, mobile apps, and IoT devices. To get a refresh token, applications typically require confidential clients with authentication.

saml oauth agent user
(Source: cloudsundial.com)

When revoking an application’s access in a dashboard, you’re killing its refresh token. This gives you the ability to force the clients to rotate secrets.

In a nutshell, a JWT (pronounced “jot”) is a secure and trustworthy standard for token authentication. One of the biggest pain points of OAuth for developers is having to manage the refresh tokens.

You get the benefits of key rotation, but you’ve just created a lot of pain for developers. API keys are very convenient for the developer but very bad for security.

Getting developers to do OAuth flows increases security, but there’s more friction. There are opportunities for toolkits and platforms to simplify things and help with token management.

Luckily, OAuth is pretty mature these days, and chances are your favorite language or framework has tools available to simplify things. Once the user takes that authorization grant and hands that to the application, the client application no longer needs to use the browser to complete the OAuth flow to get the tokens.

oauth2 oauth flow server web vs tutorial learn wikitechy programs examples
(Source: www.wikitechy.com)

The tokens are meant to be consumed by the client application so it can access resources on your behalf. The back channel is an HTTP call directly from the client application to the resource server to exchange the authorization grant for tokens.

For example, a Front Channel Flow where you authorize via an user agent might look as follows: Authorization Server returns a consent dialog saying “do you allow this application to have access to these scopes?” Of course, you’ll need to authenticate to the application, so if you’re not authenticated to your Resource Server, it’ll ask you to log in.

If you already have a cached session cookie, you’ll just see the consent dialog box. The authorization grant is passed back to the application via browser redirect.

To learn more about RSF, see Done's “Cross-Site Request Forgery explained.” Response The code returned is the authorization grant and state is to ensure it's not forged and it's from the same request.

The reason it’s called the implicit flow is that all the communication is happening through the browser. There is no backend server redeeming the authorization grant for an access token.

oauth2 framework protected obtain resources login grant credentials client
(Source: oauth2framework.wordpress.com)

An access token is returned directly from the authorization request (front channel only). It assumes the Resource Owner and Public Client are on the same device.

The front channel flow is used by the client application to obtain an authorization code grant. It assumes the Resource Owner and Client Application are on separate devices.

It supports shared secrets or assertions as client credentials signed with either symmetric or asymmetric keys. There’s also a legacy mode called Resource Owner Password Flow.

This is very similar to the direct authentication with username and password scenario and is not recommended. It’s a legacy grant type for native username/password apps such as desktop applications.

In this flow, you send the client application a username and password and it returns an access token from the Authorization Server. It typically does not support refresh tokens and it assumes the Resource Owner and Public Client are on the same device.

oauth authentication flow salesforce user agent password tutorial application learn process example token username wikitechy microsoft oauth2 rest api
(Source: www.wikitechy.com)

This is great for companies that have invested in SAML or SAML-related technologies and allow them to integrate with OAuth. We’ve covered six different flows using the different actors and token types.

There’s been a lot of people trying to exploit OAuth between applications and it’s easy to do if you don’t follow recommended Web Security 101 guidelines. Always use CSRF tokens with the state parameter to ensure flow integrity.

The biggest complaint about OAuth, in general, comes from Security people. However, in the end, a JWT is just a string of characters, so they can easily be copied and used in an Authorization header.

OAuth decouples your authorization policy decisions from authentication. It can replace traditional Web Access Management (WAM) Policies.

It’s also great for restricting and revoking permissions when building apps that can access specific APIs. It ensures only managed and/or compliant devices can access specific APIs.

flow oauth implicit user agent grant
(Source: docs.axway.com)

It has deep integration with identity provisioning workflows to revoke all tokens from a user or device. Because OAuth is an authorization framework and not a protocol, you may have interoperability issues.

There are lots of variances in how teams implement OAuth and you might need custom code to integrate with vendors. There’s a huge number of additions that’ve happened to OAuth in the last several years.

These add complexity back on top of OAuth to complete a variety of enterprise scenarios. For example, JWTs can be used as interoperable tokens that can be signed and encrypted.

Login with OAuth was made famous by Facebook Connect and Twitter. People invented this fake endpoint as a way of getting back a user profile with an access token.

You can typically answer these questions with SAML assertions, not with access tokens and authorization grants. OpenID Connect (IDC) extends OAuth 2.0 with a new signed id_token for the client and a Serif endpoint to fetch user attributes.

obtain oauth2 framework protected resources login grant password owner resource
(Source: oauth2framework.wordpress.com)

Unlike SAML, IDC provides a standard set of scopes and claims for identities. Examples include: profile, email, address, and phone.

IDC was created to be internet scalable by making things completely dynamic. There’s no longer downloading metadata and federation like SAML requires.

It supports high assurance levels and key SAML use cases for enterprises. IDC was made famous by Google and Microsoft, both big early adopters.

All that changes in the initial request is it contains standard scopes (like OpenID and email): RequestResponse The code returned is the authorization grant and state is to ensure it's not forged and it's from the same request.

Get JWT signature keys and optionally, dynamically register the Client application. Validate JWT ID token locally based on built-in dates and signatures.

oauth openam authorization oauth2 process diagram admin code sequence guide grant managing chapter client supports
(Source: docs.forgerock.org)

Get additional user attributes as needed with an access token. OKTA is best known for its single sign-on services that allow you to seamlessly authenticate to the applications you use on a daily basis.

Secure single sign-on often uses SAML as the protocol of choice, but OKTA also provides several other options, including a Sign-in Widget, Auth SDK (a JavaScript-based library), Social Login, and an Authentication API for any client. If you’re interested in learning about OKTA straight from the source, you should attend Oktane17 in late August.

If you’d rather watch a video to learn about OAuth, please see the presentation below from Karl Guinness, Senior Director of Identity at OKTA. OAuth 2.0 is an authorization framework for delegated access to APIs.

It involves clients that request scopes that Resource Owners authorize/give consent to. There are multiple flows to address varying client and authorization scenarios.

Changes to the authentication configuration will only take effect after you publish your bot. Power Virtual Agents supports a set of different authentication options, each targeted to a different usage scenario.

flow code authorization oauth oauth2 implicit diagram spring jwt grant authentication token works application access auth example vk protocol type
(Source: www.digitalocean.com)

The following variables will be available in the authoring canvas after the Only for Teams option is selected: Make sure to correct any topics with errors before publishing your bot.

The following variables will be available in the authoring canvas after manual authentication is configured: Once the configuration is saved, make sure to publish your bot so the changes take effect.

Ensure that the app has the correct API permissions and its related scopes. Sign in to the Azure portal, using an admin account on the same tenant as your Power Virtual Agents chatbot.

Enter a description (one will be provided if you leave this blank), and select the expiry period. Select the shortest period that will be relevant for the life of your bot.

Take note of the secret's Value and store this in a temporary place (such as an open Notepad document), as you'll enter it in your bot's authentication settings. This section shows an example of Azure AD being configured as an OAuth provider.

oauth social sign agent
(Source: cloudsundial.com)

If you select another service provider, you might have fewer fields to configure. If you're using Azure AD as your identity provider, ensure you log in on the same tenant where you created the app registration.

Enter the information as described for each of the fields in the following table. If you have questions about the required information, contact your administrator or identity provider.

The examples provided below are for an Azure AD common endpoint. Field nameDescriptionWhere to get this information for Azure Connection nameFriendly name for your identity provider connection.

This can be any string, but can't be changed once configured. Not applicable. Service Providers field can't be edited because Power Virtual Agents only supports generic OAuth2 providers. Not applicable. Client Your client ID obtained from the identity provider. On the app registration's Overview page as Application (client) ID. Client Secretion client secret obtained from the identity provider registration. When generating a new client secret. If you navigate away from the Certificates & secrets page, the secret's Value will be obfuscated and you'll need to create a new one. Token exchange URL (required for single sign-on)This is an optional field used when configuring single sign-on.

. Refresh Body TemplateTemplate for the refresh body. Use refresh_token={RefreshToken}redirect_URI={Redirected}grant_type=refresh_token&client_id={Client}client_secret={ClientSecret}. ScopesList of scopes you want authenticated users to have once signed in. Make sure you're only setting the necessary scopes, and follow the Least privilege access control principle. For example, User. Read.

oauth flow client credentials agent user implicit oauth2
(Source: deepakpol.wordpress.com)

Note: If you're using a custom scope, use the full URI including the exposed Application ID URI. On the API permissions page, note the scopes listed under the API / Permissions name section. For example, if your custom scope name is app.scope.SSO, and the Application ID URI is api://1234-4567, then you would enter api://1234-4567/app.scope.SSO as the scope. Token URL Template URL Template for tokens, provided by your identity provider.

Keys in the query string template will vary depending on the identity provider. Use ?client_id={Client}response_type=code&redirect_URI={Redirected}scope={Scopes}state={State}. If you want to clear the configuration from Azure Bot Service, you will need to contact your subscription owner, who will need to follow these steps.

If these steps can't be followed, contact your Microsoft Support manager to have the issue resolved. If used, the app has access to the OAuth authorization grant as well as the user's credentials, leaving this data vulnerable to recording or malicious use.

Embedded user agents also don't share authentication state, meaning no single sign-on benefits can be conferred. When the built-in browser is employed by the user for all native app logins, certain advantages are conferred, such as the ability to use a single sign-on session stored in a central location and additional security afforded by an authentication context that is separated from the app.

When implementing OAuth 2.0, there are a number of security considerations that developers must be mindful of when using the best current practice with an external user agent. Using the redirect options above means that the authorization code can only be received by native apps on the same device.

clients oauth wso2 implicit typically grant type these
(Source: docs.wso2.com)

The Proof Key for Code Exchange (Pace) protocol was created to defend against this attack vector. In most cases, native apps are considered public clients and must be registered with the authorization server.

User authentication and consent will be required by the authorization server, as per any other web browser based OAuth 2.0 flows. The reason for this is that the app can then access not only the OAuth authorization grant, but also the user's full authentication credentials.

In addition, embedded user agents don't share authentication state with other apps or the browser and therefore disabling single sign-on benefits. Using an external user agent for OAuth 2.0 authorization requests provides better security as well as an improved user experience as it enables single sign-on across the device's apps and browser.

Auth0 provides a centralized login approach that adheres to the OAuth 2.0 Best Current Practice for native apps. Centralized login provides the most secure experience and is also easy to implement for developers.

A URI is used to trigger an authentication request and the centralized login page is shown to users. Auth0 provides extensive documentation to help you easily implement the appropriate flows to keep your apps secure and user -friendly as well.

workflow oauth diagram flow oidc authorization client code isam oauth2 server ibm agent user resource workflows owner openid knowledgecenter config
(Source: www.ibm.com)

If it lives on the device or in the browser, it's a public client. What type of client you have, determines which OAuth grants to use.

On public clients, you cannot have the client itself authenticate with the authorization server (only the user is authenticated) and therefore you can't get refresh tokens from the authorization server. Example: Suppose you have a slideshow app (the client) on your iPad that wants to access your Flickr photos.

If that app asked you (the resource owner) to provide your Flickr credentials so that it can access your photos, then you, being a security-wise user, would not do so: you have no idea what that app might do with your credentials. Luckily, rather than asking for your credentials, it instead brings forward your iPad browser (your user agent), which you trust, to login to Flickr.

You sleep well at night knowing that the slideshow app did not take your credentials and do something naughty with them. The whole point of the protocol is that users should not trust arbitrary applications with their credentials.

Other Articles You Might Be Interested In

01: Definition Of User Agent
02: Detecting User Agent Browser Version
03: Device Atlas User Agent Tester
04: Device User Agent Strings
05: Best Wget User Agent
06: Googlebot User Agent String
07: Google Chrome Change User Agent String
08: Google Chrome User Agent Mobile
09: Google Chrome User Agent String
10: Google Chrome User Agent Windows
Sources
1 developers.whatismybrowser.com - https://developers.whatismybrowser.com/useragents/explore/software_name/chrome/
2 winaero.com - https://winaero.com/change-user-agent-chrome/
3 www.whatismybrowser.com - https://www.whatismybrowser.com/guides/the-latest-user-agent/chrome
4 info.greatis.com - https://info.greatis.com/guide/windows10/change-user-agent-google-chrome/
5 developers.google.com - https://developers.google.com/search/docs/advanced/crawling/overview-google-crawlers
6 www.softpedia.com - https://www.softpedia.com/get/Internet/Internet-Applications-Addons/Chrome-Extensions/Random-User-Agent.shtml
7 www.omgchrome.com - https://www.omgchrome.com/user-agent-switcher-extension-for-chrome/
8 specopssoft.com - https://specopssoft.com/blog/configuring-chrome-and-firefox-for-windows-integrated-authentication/