[AC-1637] Sanitize Business and Organization Names from html script injection prior to storing in db (#3302)

* [AC-1637] Added HtmlEncodingStringConverter to encode/decode special chars on JSON serialization/deserialization

* [AC-1637] Added unit tests for HtmlEncodingStringConverter

* [AC-1637] Moved expected values on unit tests to the arrange phase

* [AC-1637] Added HtmlEncodingStringConverter to properties that are for input/output of Org Name and Business name

* [AC-1637] Modified views in Admin project to decode values to display

* [AC-1637] Replaced Html.Raw with HttpUtility.HtmlDecode

* [AC-1637] Added JsonConverter to Provider DTOs

* [AC-1637] Modified HandlebarsMailService to decode organization name before sending emails

* Revert "[AC-1637] Added JsonConverter to Provider DTOs"

This reverts commit 94d507cf93e4c9f7f02890b9286dba90bad3f516.

* [AC-1637] Fixed Admin panel organization search

* [AC-1637] Sanitizing Organization name and business name on creation in Admin panel

* [AC-1637] Sanitizing organization name and business name on creation by a provider

* [AC-1637] Sanitizing provider name on creation and on viewing in admin panel

* [AC-1637] Added sanitization to more places where Org name is used

* [AC-1637] Swapped using HttpUtility for WebUtility since the later is part of the dotnet framework

* [AC-1637] Updated error messages

* [AC-1637] Decoding on Admin panel add existing organization

* [AC-1637] Fix HTML decoding issues

* [AC-1637] Refactor HTML decoding in View and Model classes on Admin panel

* [AC-1637] Refactor provider name and business name usages to use methods that output decoded values

* [AC-1637] Fixed typo

* [AC-1637] Renamed Provider methods to retrieve Decoded Name and BusinessName

* [AC-1637] Renamed Organization methods to retrieve Decoded Name and BusinessName

* [AC-1637] Update the display name method in the `ProviderOrganizationOrganizationDetails` class to `DisplayName()`

bitwarden_license/src/Commercial.Core/AdminConsole/Services/ProviderService.cs

@@ -257,7 +257,7 @@ public class ProviderService : IProviderService
 
                 await _providerUserRepository.ReplaceAsync(providerUser);
                 events.Add((providerUser, EventType.ProviderUser_Confirmed, null));
-                await _mailService.SendProviderConfirmedEmailAsync(provider.Name, user.Email);
+                await _mailService.SendProviderConfirmedEmailAsync(provider.DisplayName(), user.Email);
                 result.Add(Tuple.Create(providerUser, ""));
             }
             catch (BadRequestException e)
@@ -331,7 +331,7 @@ public class ProviderService : IProviderService
                 var email = user == null ? providerUser.Email : user.Email;
                 if (!string.IsNullOrWhiteSpace(email))
                 {
-                    await _mailService.SendProviderUserRemoved(provider.Name, email);
+                    await _mailService.SendProviderUserRemoved(provider.DisplayName(), email);
                 }
 
                 result.Add(Tuple.Create(providerUser, ""));
@@ -586,7 +586,7 @@ public class ProviderService : IProviderService
         var nowMillis = CoreHelpers.ToEpocMilliseconds(DateTime.UtcNow);
         var token = _dataProtector.Protect(
             $"ProviderUserInvite {providerUser.Id} {providerUser.Email} {nowMillis}");
-        await _mailService.SendProviderInviteEmailAsync(provider.Name, providerUser, token, providerUser.Email);
+        await _mailService.SendProviderInviteEmailAsync(provider.DisplayName(), providerUser, token, providerUser.Email);
     }
 
     private async Task<bool> HasConfirmedProviderAdminExceptAsync(Guid providerId, IEnumerable<Guid> providerUserIds)

bitwarden_license/src/Sso/Controllers/AccountController.cs

@@ -26,6 +26,7 @@ using IdentityModel;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
+using AuthenticationSchemes = Bit.Core.AuthenticationSchemes;
 using DIM = Duende.IdentityServer.Models;
 
 namespace Bit.Sso.Controllers;
@@ -483,7 +484,7 @@ public class AccountController : Controller
             if (orgUser.Status == OrganizationUserStatusType.Invited)
             {
                 // Org User is invited - they must manually accept the invite via email and authenticate with MP
-                throw new Exception(_i18nService.T("UserAlreadyInvited", email, organization.Name));
+                throw new Exception(_i18nService.T("UserAlreadyInvited", email, organization.DisplayName()));
             }
 
             // Accepted or Confirmed - create SSO link and return;
@@ -516,7 +517,7 @@ public class AccountController : Controller
                         await _organizationService.AdjustSeatsAsync(orgId, initialSeatCount - organization.Seats.Value, prorationDate);
                     }
                     _logger.LogInformation(e, "SSO auto provisioning failed");
-                    throw new Exception(_i18nService.T("NoSeatsAvailable", organization.Name));
+                    throw new Exception(_i18nService.T("NoSeatsAvailable", organization.DisplayName()));
                 }
             }
         }

src/Admin/AdminConsole/Controllers/OrganizationsController.cs

@@ -1,4 +1,5 @@
-using Bit.Admin.AdminConsole.Models;
+using System.Net;
+using Bit.Admin.AdminConsole.Models;
 using Bit.Admin.Enums;
 using Bit.Admin.Services;
 using Bit.Admin.Utilities;
@@ -119,8 +120,9 @@ public class OrganizationsController : Controller
             count = 1;
         }
 
+        var encodedName = WebUtility.HtmlEncode(name);
         var skip = (page - 1) * count;
-        var organizations = await _organizationRepository.SearchAsync(name, userEmail, paid, skip, count);
+        var organizations = await _organizationRepository.SearchAsync(encodedName, userEmail, paid, skip, count);
         return View(new OrganizationsModel
         {
             Items = organizations as List<Organization>,

src/Admin/AdminConsole/Controllers/ProvidersController.cs

@@ -1,4 +1,5 @@
-using Bit.Admin.AdminConsole.Models;
+using System.Net;
+using Bit.Admin.AdminConsole.Models;
 using Bit.Admin.Enums;
 using Bit.Admin.Utilities;
 using Bit.Core;
@@ -188,8 +189,9 @@ public class ProvidersController : Controller
             count = 1;
         }
 
+        var encodedName = WebUtility.HtmlEncode(name);
         var skip = (page - 1) * count;
-        var unassignedOrganizations = await _organizationRepository.SearchUnassignedToProviderAsync(name, ownerEmail, skip, count);
+        var unassignedOrganizations = await _organizationRepository.SearchUnassignedToProviderAsync(encodedName, ownerEmail, skip, count);
         var viewModel = new OrganizationUnassignedToProviderSearchViewModel
         {
             OrganizationName = string.IsNullOrWhiteSpace(name) ? null : name,
@@ -199,7 +201,7 @@ public class ProvidersController : Controller
             Items = unassignedOrganizations.Select(uo => new OrganizationSelectableViewModel
             {
                 Id = uo.Id,
-                Name = uo.Name,
+                Name = uo.DisplayName(),
                 PlanType = uo.PlanType
             }).ToList()
         };

src/Admin/AdminConsole/Models/OrganizationEditModel.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel.DataAnnotations;
+using System.Net;
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.AdminConsole.Entities.Provider;
 using Bit.Core.AdminConsole.Enums.Provider;
@@ -36,8 +37,8 @@ public class OrganizationEditModel : OrganizationViewModel
         BillingInfo = billingInfo;
         BraintreeMerchantId = globalSettings.Braintree.MerchantId;
 
-        Name = org.Name;
+        Name = org.DisplayName();
-        BusinessName = org.BusinessName;
+        BusinessName = org.DisplayBusinessName();
         BillingEmail = provider?.Type == ProviderType.Reseller ? provider.BillingEmail : org.BillingEmail;
         PlanType = org.PlanType;
         Plan = org.Plan;
@@ -184,8 +185,8 @@ public class OrganizationEditModel : OrganizationViewModel
 
     public Organization ToOrganization(Organization existingOrganization)
     {
-        existingOrganization.Name = Name;
+        existingOrganization.Name = WebUtility.HtmlEncode(Name.Trim());
-        existingOrganization.BusinessName = BusinessName;
+        existingOrganization.BusinessName = WebUtility.HtmlEncode(BusinessName.Trim());
         existingOrganization.BillingEmail = BillingEmail?.ToLowerInvariant()?.Trim();
         existingOrganization.PlanType = PlanType.Value;
         existingOrganization.Plan = Plan;

src/Admin/AdminConsole/Models/ProviderEditModel.cs

@@ -11,8 +11,8 @@ public class ProviderEditModel : ProviderViewModel
     public ProviderEditModel(Provider provider, IEnumerable<ProviderUserUserDetails> providerUsers, IEnumerable<ProviderOrganizationOrganizationDetails> organizations)
         : base(provider, providerUsers, organizations)
     {
-        Name = provider.Name;
+        Name = provider.DisplayName();
-        BusinessName = provider.BusinessName;
+        BusinessName = provider.DisplayBusinessName();
         BillingEmail = provider.BillingEmail;
         BillingPhone = provider.BillingPhone;
     }

src/Admin/AdminConsole/Views/Organizations/Edit.cshtml

@@ -4,7 +4,7 @@
 @inject Bit.Admin.Services.IAccessControlService AccessControlService
 @model OrganizationEditModel
 @{
-    ViewData["Title"] = (Model.Provider != null ? "Client " : string.Empty) + "Organization: " + Model.Organization.Name;
+    ViewData["Title"] = (Model.Provider != null ? "Client " : string.Empty) + "Organization: " + Model.Name;
 
     var canViewOrganizationInformation = AccessControlService.UserHasPermission(Permission.Org_OrgInformation_View);
     var canViewBillingInformation = AccessControlService.UserHasPermission(Permission.Org_BillingInformation_View);
@@ -58,7 +58,7 @@
     </script>
 }
 
-<h1>@(Model.Provider != null ? "Client " : string.Empty)Organization <small>@Model.Organization.Name</small></h1>
+<h1>@(Model.Provider != null ? "Client " : string.Empty)Organization <small>@Model.Name</small></h1>
 
 @if (Model.Provider != null)
 {

src/Admin/AdminConsole/Views/Organizations/Index.cshtml

@@ -46,7 +46,7 @@
                 {
                     <tr>
                         <td>
-                            <a asp-action="@Model.Action" asp-route-id="@org.Id">@org.Name</a>
+                            <a asp-action="@Model.Action" asp-route-id="@org.Id">@org.DisplayName()</a>
                         </td>
                         <td>
                             @org.Plan

src/Admin/AdminConsole/Views/Organizations/View.cshtml

@@ -1,10 +1,10 @@
 @inject Bit.Core.Settings.GlobalSettings GlobalSettings
 @model OrganizationViewModel
 @{
-    ViewData["Title"] = "Organization: " + Model.Organization.Name;
+    ViewData["Title"] = "Organization: " + Model.Organization.DisplayName();
 }
 
-<h1>Organization <small>@Model.Organization.Name</small></h1>
+<h1>Organization <small>@Model.Organization.DisplayName()</small></h1>
 
 @if (Model.Provider != null)
 {

src/Admin/AdminConsole/Views/Organizations/_ProviderInformation.cshtml

@@ -2,7 +2,7 @@
 @model Bit.Core.AdminConsole.Entities.Provider.Provider
 <dl class="row">
     <dt class="col-sm-4 col-lg-3">Provider Name</dt>
-    <dd class="col-sm-8 col-lg-9">@Model.Name</dd>
+    <dd class="col-sm-8 col-lg-9">@Model.DisplayName()</dd>
 
     <dt class="col-sm-4 col-lg-3">Provider Type</dt>
     <dd class="col-sm-8 col-lg-9">@(Model.Type.GetDisplayAttribute()?.GetName())</dd>

src/Admin/AdminConsole/Views/Providers/AddExistingOrganization.cshtml

@@ -45,7 +45,7 @@
                             @Html.HiddenFor(m => Model.Items[i].Id, new { @readonly = "readonly", autocomplete = "off" })
                             @Html.CheckBoxFor(m => Model.Items[i].Selected)
                         </td>
-                        <td>@Html.ActionLink(Model.Items[i].Name, "Edit", "Organizations", new { id = Model.Items[i].Id }, new { target = "_blank" })</td>
+                        <td>@Html.ActionLink(Model.Items[i].DisplayName(), "Edit", "Organizations", new { id = Model.Items[i].Id }, new { target = "_blank" })</td>
                         <td>@(Model.Items[i].PlanType.GetDisplayAttribute()?.Name ?? Model.Items[i].PlanType.ToString())</td>
                     </tr>
                 }

src/Admin/AdminConsole/Views/Providers/Edit.cshtml

@@ -3,12 +3,12 @@
 
 @model ProviderEditModel
 @{
-    ViewData["Title"] = "Provider: " + Model.Provider.Name;
+    ViewData["Title"] = "Provider: " + Model.Provider.DisplayName();
 
     var canEdit = AccessControlService.UserHasPermission(Permission.Provider_Edit);
 }
 
-<h1>Provider <small>@Model.Provider.Name</small></h1>
+<h1>Provider <small>@Model.Provider.DisplayName()</small></h1>
 
 <h2>Provider Information</h2>
 @await Html.PartialAsync("_ViewInformation", Model)
@@ -17,12 +17,12 @@
     <h2>General</h2>
     <dl class="row">
         <dt class="col-sm-4 col-lg-3">Name</dt>
-        <dd class="col-sm-8 col-lg-9">@Model.Provider.Name</dd>
+        <dd class="col-sm-8 col-lg-9">@Model.Provider.DisplayName()</dd>
     </dl>
     <h2>Business Information</h2>
     <dl class="row">
         <dt class="col-sm-4 col-lg-3">Business Name</dt>
-        <dd class="col-sm-8 col-lg-9">@Model.Provider.BusinessName</dd>
+        <dd class="col-sm-8 col-lg-9">@Model.Provider.DisplayBusinessName()</dd>
     </dl>
     <h2>Billing</h2>
     <div class="row">

src/Admin/AdminConsole/Views/Providers/Index.cshtml

@@ -52,7 +52,7 @@
                 {
                     <tr>
                         <td>
-                            <a asp-action="@Model.Action" asp-route-id="@provider.Id">@(provider.Name ?? "Pending")</a>
+                            <a asp-action="@Model.Action" asp-route-id="@provider.Id">@(!string.IsNullOrEmpty(provider.DisplayName()) ? provider.DisplayName() : "Pending")</a>
                         </td>
                         <td>@provider.Type.GetDisplayAttribute()?.GetShortName()</td>
                         <td>@provider.Status</td>

src/Admin/AdminConsole/Views/Providers/Organizations.cshtml

@@ -45,7 +45,7 @@
                         {
                             <tr>
                                 <td class="align-middle">
-                                    <a asp-controller="Organizations" asp-action="Edit" asp-route-id="@providerOrganization.OrganizationId">@providerOrganization.OrganizationName</a>
+                                    <a asp-controller="Organizations" asp-action="Edit" asp-route-id="@providerOrganization.OrganizationId">@providerOrganization.DisplayName()</a>
                                 </td>
                                 <td>
                                     @providerOrganization.Status

src/Admin/AdminConsole/Views/Providers/View.cshtml

@@ -1,9 +1,9 @@
 @model ProviderViewModel
 @{
-    ViewData["Title"] = "Provider: " + Model.Provider.Name;
+    ViewData["Title"] = "Provider: " + Model.Provider.DisplayName();
 }
 
-<h1>Provider <small>@Model.Provider.Name</small></h1>
+<h1>Provider <small>@Model.Provider.DisplayName()</small></h1>
 
 <h2>Information</h2>
 @await Html.PartialAsync("_ViewInformation", Model)

src/Admin/AdminConsole/Views/Shared/_OrganizationForm.cshtml

@@ -28,7 +28,7 @@
             <div class="col-sm">
                 <div class="form-group">
                     <label asp-for="Name"></label>
-                    <input type="text" class="form-control" asp-for="Name" required>
+                    <input type="text" class="form-control" asp-for="Name" value="@Model.Name" required>
                 </div>
             </div>
         </div>
@@ -68,7 +68,7 @@
             <div class="col-sm">
                 <div class="form-group">
                     <label asp-for="BusinessName"></label>
-                    <input type="text" class="form-control" asp-for="BusinessName">
+                    <input type="text" class="form-control" asp-for="BusinessName" value="@Model.BusinessName">
                 </div>
             </div>
         </div>

src/Api/AdminConsole/Controllers/OrganizationsController.cs

@@ -303,7 +303,7 @@ public class OrganizationsController : Controller
             throw new NotFoundException();
         }
 
-        var updateBilling = !_globalSettings.SelfHosted && (model.BusinessName != organization.BusinessName ||
+        var updateBilling = !_globalSettings.SelfHosted && (model.BusinessName != organization.DisplayBusinessName() ||
                                                             model.BillingEmail != organization.BillingEmail);
 
         var hasRequiredPermissions = updateBilling

src/Api/AdminConsole/Models/Request/Organizations/OrganizationCreateRequestModel.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
 using Bit.Core.Entities;
 using Bit.Core.Enums;
 using Bit.Core.Models.Business;
@@ -9,9 +10,11 @@ namespace Bit.Api.AdminConsole.Models.Request.Organizations;
 public class OrganizationCreateRequestModel : IValidatableObject
 {
     [Required]
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Business Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string BusinessName { get; set; }
     [Required]
     [StringLength(256)]

src/Api/AdminConsole/Models/Request/Organizations/OrganizationUpdateRequestModel.cs

@@ -1,16 +1,20 @@
 using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.Models.Data;
 using Bit.Core.Settings;
+using Bit.Core.Utilities;
 
 namespace Bit.Api.AdminConsole.Models.Request.Organizations;
 
 public class OrganizationUpdateRequestModel
 {
     [Required]
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Business Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string BusinessName { get; set; }
     [EmailAddress]
     [Required]

src/Api/AdminConsole/Models/Request/Providers/ProviderSetupRequestModel.cs

@@ -1,14 +1,18 @@
 using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
 using Bit.Core.AdminConsole.Entities.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Api.AdminConsole.Models.Request.Providers;
 
 public class ProviderSetupRequestModel
 {
     [Required]
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Business Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string BusinessName { get; set; }
     [Required]
     [StringLength(256)]

src/Api/AdminConsole/Models/Request/Providers/ProviderUpdateRequestModel.cs

@@ -1,15 +1,19 @@
 using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
 using Bit.Core.AdminConsole.Entities.Provider;
 using Bit.Core.Settings;
+using Bit.Core.Utilities;
 
 namespace Bit.Api.AdminConsole.Models.Request.Providers;
 
 public class ProviderUpdateRequestModel
 {
     [Required]
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
-    [StringLength(50)]
+    [StringLength(50, ErrorMessage = "The field Business Name exceeds the maximum length.")]
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string BusinessName { get; set; }
     [EmailAddress]
     [Required]

src/Api/AdminConsole/Models/Response/Organizations/OrganizationResponseModel.cs

@@ -1,4 +1,5 @@
-using Bit.Api.Models.Response;
+using System.Text.Json.Serialization;
+using Bit.Api.Models.Response;
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.Enums;
 using Bit.Core.Models.Api;
@@ -60,7 +61,9 @@ public class OrganizationResponseModel : ResponseModel
     }
 
     public Guid Id { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string BusinessName { get; set; }
     public string BusinessAddress1 { get; set; }
     public string BusinessAddress2 { get; set; }

src/Api/AdminConsole/Models/Response/ProfileOrganizationResponseModel.cs

@@ -1,4 +1,5 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
 using Bit.Core.Auth.Enums;
 using Bit.Core.Auth.Models.Data;
 using Bit.Core.Enums;
@@ -103,6 +104,7 @@ public class ProfileOrganizationResponseModel : ResponseModel
     }
 
     public Guid Id { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public bool UsePolicies { get; set; }
     public bool UseSso { get; set; }
@@ -135,6 +137,7 @@ public class ProfileOrganizationResponseModel : ResponseModel
     public Guid? UserId { get; set; }
     public bool HasPublicAndPrivateKeys { get; set; }
     public Guid? ProviderId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string ProviderName { get; set; }
     public ProviderType? ProviderType { get; set; }
     public string FamilySponsorshipFriendlyName { get; set; }

src/Api/AdminConsole/Models/Response/Providers/ProfileProviderResponseModel.cs

@@ -1,4 +1,5 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
 using Bit.Core.AdminConsole.Models.Data.Provider;
 using Bit.Core.Models.Api;
 using Bit.Core.Models.Data;
@@ -23,6 +24,7 @@ public class ProfileProviderResponseModel : ResponseModel
     }
 
     public Guid Id { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public string Key { get; set; }
     public ProviderUserStatusType Status { get; set; }

src/Api/AdminConsole/Models/Response/Providers/ProviderOrganizationResponseModel.cs

@@ -1,6 +1,8 @@
-using Bit.Core.AdminConsole.Entities.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Entities.Provider;
 using Bit.Core.AdminConsole.Models.Data.Provider;
 using Bit.Core.Models.Api;
+using Bit.Core.Utilities;
 
 namespace Bit.Api.AdminConsole.Models.Response.Providers;
 
@@ -68,5 +70,6 @@ public class ProviderOrganizationOrganizationDetailsResponseModel : ProviderOrga
         OrganizationName = providerOrganization.OrganizationName;
     }
 
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string OrganizationName { get; set; }
 }

src/Api/AdminConsole/Models/Response/Providers/ProviderResponseModel.cs

@@ -1,5 +1,7 @@
-using Bit.Core.AdminConsole.Entities.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Entities.Provider;
 using Bit.Core.Models.Api;
+using Bit.Core.Utilities;
 
 namespace Bit.Api.AdminConsole.Models.Response.Providers;
 
@@ -25,6 +27,7 @@ public class ProviderResponseModel : ResponseModel
     }
 
     public Guid Id { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public string BusinessName { get; set; }
     public string BusinessAddress1 { get; set; }

src/Api/Controllers/OrganizationSponsorshipsController.cs

@@ -132,7 +132,7 @@ public class OrganizationSponsorshipsController : Controller
         }
 
         var (syncResponseData, offersToSend) = await _syncSponsorshipsCommand.SyncOrganization(sponsoringOrg, model.ToOrganizationSponsorshipSync().SponsorshipsBatch);
-        await _sendSponsorshipOfferCommand.BulkSendSponsorshipOfferAsync(sponsoringOrg.Name, offersToSend);
+        await _sendSponsorshipOfferCommand.BulkSendSponsorshipOfferAsync(sponsoringOrg.DisplayName(), offersToSend);
         return new OrganizationSponsorshipSyncResponseModel(syncResponseData);
     }
 

src/Api/Jobs/SelfHostedSponsorshipSyncJob.cs

@@ -58,7 +58,7 @@ public class SelfHostedSponsorshipSyncJob : BaseJob
                     }
                     catch (Exception ex)
                     {
-                        _logger.LogError(ex, $"Sponsorship sync for organization {org.Name} Failed");
+                        _logger.LogError(ex, "Sponsorship sync for organization {OrganizationName} Failed", org.DisplayName());
                     }
                 }
             }

src/Billing/Controllers/FreshsalesController.cs

@@ -95,7 +95,7 @@ public class FreshsalesController : Controller
 
             foreach (var org in orgs)
             {
-                noteItems.Add($"Org, {org.Name}: {_globalSettings.BaseServiceUri.Admin}/organizations/edit/{org.Id}");
+                noteItems.Add($"Org, {org.DisplayName()}: {_globalSettings.BaseServiceUri.Admin}/organizations/edit/{org.Id}");
                 if (TryGetPlanName(org.PlanType, out var planName))
                 {
                     newTags.Add($"Org: {planName}");

src/Core/AdminConsole/Entities/Organization.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel.DataAnnotations;
+using System.Net;
 using System.Text.Json;
 using Bit.Core.Auth.Enums;
 using Bit.Core.Auth.Models;
@@ -17,8 +18,14 @@ public class Organization : ITableObject<Guid>, IStorableSubscriber, IRevisable,
     public Guid Id { get; set; }
     [MaxLength(50)]
     public string Identifier { get; set; }
+    /// <summary>
+    /// This value is HTML encoded. For display purposes use the method DisplayName() instead.
+    /// </summary>
     [MaxLength(50)]
     public string Name { get; set; }
+    /// <summary>
+    /// This value is HTML encoded. For display purposes use the method DisplayBusinessName() instead.
+    /// </summary>
     [MaxLength(50)]
     public string BusinessName { get; set; }
     [MaxLength(50)]
@@ -104,6 +111,22 @@ public class Organization : ITableObject<Guid>, IStorableSubscriber, IRevisable,
         }
     }
 
+    /// <summary>
+    /// Returns the name of the organization, HTML decoded ready for display.
+    /// </summary>
+    public string DisplayName()
+    {
+        return WebUtility.HtmlDecode(Name);
+    }
+
+    /// <summary>
+    /// Returns the business name of the organization, HTML decoded ready for display.
+    /// </summary>
+    public string DisplayBusinessName()
+    {
+        return WebUtility.HtmlDecode(BusinessName);
+    }
+
     public string BillingEmailAddress()
     {
         return BillingEmail?.ToLowerInvariant()?.Trim();
@@ -111,12 +134,12 @@ public class Organization : ITableObject<Guid>, IStorableSubscriber, IRevisable,
 
     public string BillingName()
     {
-        return BusinessName;
+        return DisplayBusinessName();
     }
 
     public string SubscriberName()
     {
-        return Name;
+        return DisplayName();
     }
 
     public string BraintreeCustomerIdPrefix()

src/Core/AdminConsole/Entities/Provider/Provider.cs

@@ -1,4 +1,5 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Net;
+using Bit.Core.AdminConsole.Enums.Provider;
 using Bit.Core.Entities;
 using Bit.Core.Utilities;
 
@@ -7,7 +8,13 @@ namespace Bit.Core.AdminConsole.Entities.Provider;
 public class Provider : ITableObject<Guid>
 {
     public Guid Id { get; set; }
+    /// <summary>
+    /// This value is HTML encoded. For display purposes use the method DisplayName() instead.
+    /// </summary>
     public string Name { get; set; }
+    /// <summary>
+    /// This value is HTML encoded. For display purposes use the method DisplayBusinessName() instead.
+    /// </summary>
     public string BusinessName { get; set; }
     public string BusinessAddress1 { get; set; }
     public string BusinessAddress2 { get; set; }
@@ -30,4 +37,20 @@ public class Provider : ITableObject<Guid>
             Id = CoreHelpers.GenerateComb();
         }
     }
+
+    /// <summary>
+    /// Returns the name of the provider, HTML decoded ready for display.
+    /// </summary>
+    public string DisplayName()
+    {
+        return WebUtility.HtmlDecode(Name);
+    }
+
+    /// <summary>
+    /// Returns the business name of the provider, HTML decoded ready for display.
+    /// </summary>
+    public string DisplayBusinessName()
+    {
+        return WebUtility.HtmlDecode(BusinessName);
+    }
 }

src/Core/AdminConsole/Models/Data/Organizations/OrganizationUsers/OrganizationUserOrganizationDetails.cs

@@ -1,4 +1,6 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.Models.Data.Organizations.OrganizationUsers;
 
@@ -6,6 +8,7 @@ public class OrganizationUserOrganizationDetails
 {
     public Guid OrganizationId { get; set; }
     public Guid? UserId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public bool UsePolicies { get; set; }
     public bool UseSso { get; set; }
@@ -37,6 +40,7 @@ public class OrganizationUserOrganizationDetails
     public string PublicKey { get; set; }
     public string PrivateKey { get; set; }
     public Guid? ProviderId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string ProviderName { get; set; }
     public ProviderType? ProviderType { get; set; }
     public string FamilySponsorshipFriendlyName { get; set; }

src/Core/AdminConsole/Models/Data/Provider/ProviderOrganizationOrganizationDetails.cs

@@ -1,4 +1,7 @@
-using Bit.Core.Enums;
+using System.Net;
+using System.Text.Json.Serialization;
+using Bit.Core.Enums;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.AdminConsole.Models.Data.Provider;
 
@@ -7,6 +10,10 @@ public class ProviderOrganizationOrganizationDetails
     public Guid Id { get; set; }
     public Guid ProviderId { get; set; }
     public Guid OrganizationId { get; set; }
+    /// <summary>
+    /// This value is HTML encoded. For display purposes use the method DisplayName() instead.
+    /// </summary>
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string OrganizationName { get; set; }
     public string Key { get; set; }
     public string Settings { get; set; }
@@ -16,4 +23,12 @@ public class ProviderOrganizationOrganizationDetails
     public int? Seats { get; set; }
     public string Plan { get; set; }
     public OrganizationStatusType Status { get; set; }
+
+    /// <summary>
+    /// Returns the name of the organization, HTML decoded ready for display.
+    /// </summary>
+    public string DisplayName()
+    {
+        return WebUtility.HtmlDecode(OrganizationName);
+    }
 }

src/Core/AdminConsole/Models/Data/Provider/ProviderOrganizationProviderDetails.cs

@@ -1,4 +1,6 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.AdminConsole.Models.Data.Provider;
 
@@ -7,6 +9,7 @@ public class ProviderOrganizationProviderDetails
     public Guid Id { get; set; }
     public Guid ProviderId { get; set; }
     public Guid OrganizationId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string ProviderName { get; set; }
     public ProviderType ProviderType { get; set; }
 }

src/Core/AdminConsole/Models/Data/Provider/ProviderUserOrganizationDetails.cs

@@ -1,4 +1,6 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.AdminConsole.Models.Data.Provider;
 
@@ -6,6 +8,7 @@ public class ProviderUserOrganizationDetails
 {
     public Guid OrganizationId { get; set; }
     public Guid? UserId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public bool UsePolicies { get; set; }
     public bool UseSso { get; set; }
@@ -33,6 +36,7 @@ public class ProviderUserOrganizationDetails
     public string PrivateKey { get; set; }
     public Guid? ProviderId { get; set; }
     public Guid? ProviderUserId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string ProviderName { get; set; }
     public Core.Enums.PlanType PlanType { get; set; }
     public bool LimitCollectionCreationDeletion { get; set; }

src/Core/AdminConsole/Models/Data/Provider/ProviderUserProviderDetails.cs

@@ -1,4 +1,6 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.AdminConsole.Models.Data.Provider;
 
@@ -6,6 +8,7 @@ public class ProviderUserProviderDetails
 {
     public Guid ProviderId { get; set; }
     public Guid? UserId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public string Key { get; set; }
     public ProviderUserStatusType Status { get; set; }

src/Core/AdminConsole/Models/Data/Provider/ProviderUserUserDetails.cs

@@ -1,4 +1,6 @@
-using Bit.Core.AdminConsole.Enums.Provider;
+using System.Text.Json.Serialization;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.AdminConsole.Models.Data.Provider;
 
@@ -7,6 +9,7 @@ public class ProviderUserUserDetails
     public Guid Id { get; set; }
     public Guid ProviderId { get; set; }
     public Guid? UserId { get; set; }
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
     public string Name { get; set; }
     public string Email { get; set; }
     public ProviderUserStatusType Status { get; set; }

src/Core/AdminConsole/Services/Implementations/OrganizationService.cs

@@ -828,7 +828,7 @@ public class OrganizationService : IOrganizationService
             await customerService.UpdateAsync(organization.GatewayCustomerId, new CustomerUpdateOptions
             {
                 Email = organization.BillingEmail,
-                Description = organization.BusinessName
+                Description = organization.DisplayBusinessName()
             });
         }
     }
@@ -1285,7 +1285,7 @@ public class OrganizationService : IOrganizationService
                 orgUser.Email = null;
 
                 await _eventService.LogOrganizationUserEventAsync(orgUser, EventType.OrganizationUser_Confirmed);
-                await _mailService.SendOrganizationConfirmedEmailAsync(organization.Name, user.Email);
+                await _mailService.SendOrganizationConfirmedEmailAsync(organization.DisplayName(), user.Email);
                 await DeleteAndPushUserRegistrationAsync(organizationId, user.Id);
                 succeededUsers.Add(orgUser);
                 result.Add(Tuple.Create(orgUser, ""));

src/Core/AdminConsole/Services/Implementations/PolicyService.cs

@@ -131,7 +131,7 @@ public class PolicyService : IPolicyService
                                 await organizationService.DeleteUserAsync(policy.OrganizationId, orgUser.Id,
                                     savingUserId);
                                 await _mailService.SendOrganizationUserRemovedForPolicyTwoStepEmailAsync(
-                                    org.Name, orgUser.Email);
+                                    org.DisplayName(), orgUser.Email);
                             }
                         }
                         break;
@@ -147,7 +147,7 @@ public class PolicyService : IPolicyService
                                 await organizationService.DeleteUserAsync(policy.OrganizationId, orgUser.Id,
                                     savingUserId);
                                 await _mailService.SendOrganizationUserRemovedForPolicySingleOrgEmailAsync(
-                                    org.Name, orgUser.Email);
+                                    org.DisplayName(), orgUser.Email);
                             }
                         }
                         break;

src/Core/Models/Mail/OrganizationInvitesInfo.cs

@@ -15,7 +15,7 @@ public class OrganizationInvitesInfo
         bool initOrganization = false
         )
     {
-        OrganizationName = org.Name;
+        OrganizationName = org.DisplayName();
         OrgSsoIdentifier = org.Identifier;
 
         IsFreeOrg = org.PlanType == PlanType.Free;

src/Core/OrganizationFeatures/OrganizationSponsorships/FamiliesForEnterprise/Cloud/SendSponsorshipOfferCommand.cs

@@ -65,6 +65,6 @@ public class SendSponsorshipOfferCommand : ISendSponsorshipOfferCommand
             throw new BadRequestException("Cannot find an outstanding sponsorship offer for this organization.");
         }
 
-        await SendSponsorshipOfferAsync(sponsorship, sponsoringOrg.Name);
+        await SendSponsorshipOfferAsync(sponsorship, sponsoringOrg.DisplayName());
     }
 }

src/Core/Services/Implementations/HandlebarsMailService.cs

@@ -145,7 +145,7 @@ public class HandlebarsMailService : IMailService
 
     public async Task SendOrganizationAutoscaledEmailAsync(Organization organization, int initialSeatCount, IEnumerable<string> ownerEmails)
     {
-        var message = CreateDefaultMessage($"{organization.Name} Seat Count Has Increased", ownerEmails);
+        var message = CreateDefaultMessage($"{organization.DisplayName()} Seat Count Has Increased", ownerEmails);
         var model = new OrganizationSeatsAutoscaledViewModel
         {
             OrganizationId = organization.Id,
@@ -160,7 +160,7 @@ public class HandlebarsMailService : IMailService
 
     public async Task SendOrganizationMaxSeatLimitReachedEmailAsync(Organization organization, int maxSeatCount, IEnumerable<string> ownerEmails)
     {
-        var message = CreateDefaultMessage($"{organization.Name} Seat Limit Reached", ownerEmails);
+        var message = CreateDefaultMessage($"{organization.DisplayName()} Seat Limit Reached", ownerEmails);
         var model = new OrganizationSeatsMaxReachedViewModel
         {
             OrganizationId = organization.Id,
@@ -179,7 +179,7 @@ public class HandlebarsMailService : IMailService
         var model = new OrganizationUserAcceptedViewModel
         {
             OrganizationId = organization.Id,
-            OrganizationName = CoreHelpers.SanitizeForEmail(organization.Name, false),
+            OrganizationName = CoreHelpers.SanitizeForEmail(organization.DisplayName(), false),
             UserIdentifier = userIdentifier,
             WebVaultUrl = _globalSettings.BaseServiceUri.VaultWithHash,
             SiteName = _globalSettings.SiteName
@@ -933,7 +933,7 @@ public class HandlebarsMailService : IMailService
     public async Task SendSecretsManagerMaxSeatLimitReachedEmailAsync(Organization organization, int maxSeatCount,
         IEnumerable<string> ownerEmails)
     {
-        var message = CreateDefaultMessage($"{organization.Name} Secrets Manager Seat Limit Reached", ownerEmails);
+        var message = CreateDefaultMessage($"{organization.DisplayName()} Secrets Manager Seat Limit Reached", ownerEmails);
         var model = new OrganizationSeatsMaxReachedViewModel
         {
             OrganizationId = organization.Id,
@@ -948,7 +948,7 @@ public class HandlebarsMailService : IMailService
     public async Task SendSecretsManagerMaxServiceAccountLimitReachedEmailAsync(Organization organization, int maxSeatCount,
         IEnumerable<string> ownerEmails)
     {
-        var message = CreateDefaultMessage($"{organization.Name} Secrets Manager Service Accounts Limit Reached", ownerEmails);
+        var message = CreateDefaultMessage($"{organization.DisplayName()} Secrets Manager Service Accounts Limit Reached", ownerEmails);
         var model = new OrganizationServiceAccountsMaxReachedViewModel
         {
             OrganizationId = organization.Id,

src/Core/Services/Implementations/LicensingService.cs

@@ -132,13 +132,13 @@ public class LicensingService : ILicensingService
     {
         _logger.LogInformation(Constants.BypassFiltersEventId, null,
             "Organization {0} ({1}) has an invalid license and is being disabled. Reason: {2}",
-            org.Id, org.Name, reason);
+            org.Id, org.DisplayName(), reason);
         org.Enabled = false;
         org.ExpirationDate = license?.Expires ?? DateTime.UtcNow;
         org.RevisionDate = DateTime.UtcNow;
         await _organizationRepository.ReplaceAsync(org);
 
-        await _mailService.SendLicenseExpiredAsync(new List<string> { org.BillingEmail }, org.Name);
+        await _mailService.SendLicenseExpiredAsync(new List<string> { org.BillingEmail }, org.DisplayName());
     }
 
     public async Task ValidateUsersAsync()

src/Core/Services/Implementations/StripePaymentService.cs

@@ -131,7 +131,7 @@ public class StripePaymentService : IPaymentService
         {
             customer = await _stripeAdapter.CustomerCreateAsync(new Stripe.CustomerCreateOptions
             {
-                Description = org.BusinessName,
+                Description = org.DisplayBusinessName(),
                 Email = org.BillingEmail,
                 Source = stipeCustomerSourceToken,
                 PaymentMethod = stipeCustomerPaymentMethodId,

src/Core/Services/Implementations/UserService.cs

@@ -797,7 +797,7 @@ public class UserService : UserManager<User>, IUserService, IDisposable
         user.ForcePasswordReset = true;
 
         await _userRepository.ReplaceAsync(user);
-        await _mailService.SendAdminResetPasswordEmailAsync(user.Email, user.Name, org.Name);
+        await _mailService.SendAdminResetPasswordEmailAsync(user.Email, user.Name, org.DisplayName());
         await _eventService.LogOrganizationUserEventAsync(orgUser, EventType.OrganizationUser_AdminResetPassword);
         await _pushService.PushLogOutAsync(user.Id);
 
@@ -1391,7 +1391,7 @@ public class UserService : UserManager<User>, IUserService, IDisposable
             await organizationService.DeleteUserAsync(p.OrganizationId, user.Id);
             var organization = await _organizationRepository.GetByIdAsync(p.OrganizationId);
             await _mailService.SendOrganizationUserRemovedForPolicyTwoStepEmailAsync(
-                organization.Name, user.Email);
+                organization.DisplayName(), user.Email);
         }).ToArray();
 
         await Task.WhenAll(removeOrgUserTasks);

src/Core/Utilities/JsonHelpers.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using System.Net;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using NS = Newtonsoft.Json;
@@ -192,3 +193,33 @@ public class PermissiveStringEnumerableConverter : JsonConverter<IEnumerable<str
         writer.WriteEndArray();
     }
 }
+
+/// <summary>
+/// Encodes incoming strings using HTML encoding
+/// and decodes outgoing strings using HTML decoding.
+/// </summary>
+public class HtmlEncodingStringConverter : JsonConverter<string>
+{
+    public override string Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        if (reader.TokenType == JsonTokenType.String)
+        {
+            var originalValue = reader.GetString();
+            return WebUtility.HtmlEncode(originalValue);
+        }
+        return reader.GetString();
+    }
+
+    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
+    {
+        if (!string.IsNullOrEmpty(value))
+        {
+            var encodedValue = WebUtility.HtmlDecode(value);
+            writer.WriteStringValue(encodedValue);
+        }
+        else
+        {
+            writer.WriteNullValue();
+        }
+    }
+}

test/Core.Test/AdminConsole/Services/OrganizationServiceTests.cs

@@ -1744,7 +1744,7 @@ OrganizationUserInvite invite, SutProvider<OrganizationService> sutProvider)
         await sutProvider.Sut.ConfirmUserAsync(orgUser.OrganizationId, orgUser.Id, key, confirmingUser.Id, userService);
 
         await sutProvider.GetDependency<IEventService>().Received(1).LogOrganizationUserEventAsync(orgUser, EventType.OrganizationUser_Confirmed);
-        await sutProvider.GetDependency<IMailService>().Received(1).SendOrganizationConfirmedEmailAsync(org.Name, user.Email);
+        await sutProvider.GetDependency<IMailService>().Received(1).SendOrganizationConfirmedEmailAsync(org.DisplayName(), user.Email);
         await organizationUserRepository.Received(1).ReplaceManyAsync(Arg.Is<List<OrganizationUser>>(users => users.Contains(orgUser) && users.Count == 1));
     }
 

test/Core.Test/AdminConsole/Services/PolicyServiceTests.cs

@@ -329,7 +329,7 @@ public class PolicyServiceTests
             .DeleteUserAsync(policy.OrganizationId, orgUserDetail.Id, savingUserId);
 
         await sutProvider.GetDependency<IMailService>().Received()
-            .SendOrganizationUserRemovedForPolicyTwoStepEmailAsync(org.Name, orgUserDetail.Email);
+            .SendOrganizationUserRemovedForPolicyTwoStepEmailAsync(org.DisplayName(), orgUserDetail.Email);
 
         await sutProvider.GetDependency<IEventService>().Received()
             .LogPolicyEventAsync(policy, EventType.Policy_Updated);

test/Core.Test/Utilities/HtmlEncodingStringConverterTests.cs

@@ -0,0 +1,89 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Bit.Core.Utilities;
+using Xunit;
+
+namespace Bit.Core.Test.Utilities;
+
+public class HtmlEncodingStringConverterTests
+{
+    [Fact]
+    public void Serialize_WhenEncodedValueIsNotNull_SerializesHtmlEncodedString()
+    {
+        // Arrange
+        var obj = new HtmlEncodedString
+        {
+            EncodedValue = "This is <b>bold</b>",
+            NonEncodedValue = "This is <b>bold</b>"
+        };
+        const string expectedJsonString = "{\"EncodedValue\":\"This is <b>bold</b>\",\"NonEncodedValue\":\"This is <b>bold</b>\"}";
+
+        // This is necessary to prevent the serializer from double encoding the string
+        var serializerOptions = new JsonSerializerOptions
+        {
+            Encoder = System.Text.Encodings.Web.JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
+        };
+
+        // Act
+        var jsonString = JsonSerializer.Serialize(obj, serializerOptions);
+
+        // Assert
+        Assert.Equal(expectedJsonString, jsonString);
+    }
+
+    [Fact]
+    public void Serialize_WhenEncodedValueIsNull_SerializesNull()
+    {
+        // Arrange
+        var obj = new HtmlEncodedString
+        {
+            EncodedValue = null,
+            NonEncodedValue = null
+        };
+        const string expectedJsonString = "{\"EncodedValue\":null,\"NonEncodedValue\":null}";
+
+        // Act
+        var jsonString = JsonSerializer.Serialize(obj);
+
+        // Assert
+        Assert.Equal(expectedJsonString, jsonString);
+    }
+
+    [Fact]
+    public void Deserialize_WhenJsonContainsHtmlEncodedString_ReturnsDecodedString()
+    {
+        // Arrange
+        const string json = "{\"EncodedValue\":\"This is <b>bold</b>\",\"NonEncodedValue\":\"This is <b>bold</b>\"}";
+        const string expectedEncodedValue = "This is &lt;b&gt;bold&lt;/b&gt;";
+        const string expectedNonEncodedValue = "This is <b>bold</b>";
+
+        // Act
+        var obj = JsonSerializer.Deserialize<HtmlEncodedString>(json);
+
+        // Assert
+        Assert.Equal(expectedEncodedValue, obj.EncodedValue);
+        Assert.Equal(expectedNonEncodedValue, obj.NonEncodedValue);
+    }
+
+    [Fact]
+    public void Deserialize_WhenJsonContainsNull_ReturnsNull()
+    {
+        // Arrange
+        const string json = "{\"EncodedValue\":null,\"NonEncodedValue\":null}";
+
+        // Act
+        var obj = JsonSerializer.Deserialize<HtmlEncodedString>(json);
+
+        // Assert
+        Assert.Null(obj.EncodedValue);
+        Assert.Null(obj.NonEncodedValue);
+    }
+}
+
+public class HtmlEncodedString
+{
+    [JsonConverter(typeof(HtmlEncodingStringConverter))]
+    public string EncodedValue { get; set; }
+
+    public string NonEncodedValue { get; set; }
+}