Intune App Configuration Bug: Ampersands Trigger Mismatch Errors - Solution Inside
Microsoft Intune provides a robust platform for unified endpoint management, allowing administrators to manage devices and applications across various operating systems, including iOS. A critical feature of Intune is the ability to deploy app configuration policies. These policies enable fine-grained control over app settings, which is essential for enterprise deployments, ensuring applications behave as required within the organizational security and compliance framework. Correctly configuring these settings is paramount for seamless user experience and operational efficiency.
App configuration policies are particularly useful for standardizing settings like connection endpoints, branding elements, security configurations, and licensing information across large numbers of devices without manual intervention. For managed iOS devices, these configurations are typically delivered using the Managed App Configuration channel provided by the Apple platform. This channel relies on XML-formatted property lists (plists) to convey the settings to the managed applications. Understanding the underlying mechanisms, such as XML formatting rules, is sometimes necessary when encountering unexpected issues, as highlighted by a specific problem related to special characters like the ampersand (&).
Understanding the Challenge: Symptoms of the Ampersand Bug¶
Consider a common scenario faced by IT administrators utilizing Microsoft Intune to manage applications on iOS devices. The process begins with creating an application configuration policy specifically targeted at managed iOS devices. This policy aims to push specific settings to a line-of-business application or a store application that supports managed configuration. Within the Intune portal, the administrator navigates to the “Apps” section, then “App configuration policies,” and proceeds to create a new policy.
During the policy creation workflow, particularly when defining the configuration settings, administrators are often presented with the option to use a “Configuration settings format.” A popular and user-friendly choice is the “Use configuration designer.” This designer provides a graphical interface where administrators can input key-value pairs for the application settings. The designer abstracts the underlying XML structure, making it easier to define simple settings without directly editing raw XML.
The issue arises when an administrator attempts to input a configuration value that contains an ampersand symbol (&). A frequent use case for such a value is a complex URL. For instance, an application might require a full Single Sign-On (SSO) authentication endpoint URL as a configuration value. This URL might include query parameters separated by ampersands, as is standard practice in web addresses. Let’s take a hypothetical example:
Configuration key: ssoAuthEndpoint
Value type: String
Configuration value: https://sso.contoso.com/idpov/accesslogin/FedSSODispatch.faces?PartnerIdpId=https://sts.windows.net/{GUID}/&TargetResource=https://sso.contoso.com/idprov/pages/home/dispatch.jsp?SpName=MBF
In this example, the ssoAuthEndpoint key is assigned a string value which is a URL containing an ampersand (&) separating the PartnerIdpId and TargetResource query parameters. While this URL is perfectly valid in the context of web browsing, entering it directly into the configuration designer’s “Configuration value” field for a String type setting can trigger an unexpected validation error.
Upon attempting to save the configuration setting by clicking “OK” within the designer interface, the Intune portal displays a specific error message. This message indicates a fundamental incompatibility detected by the designer’s validation logic. The error typically reads:
Mismatch between the value type and the configuration value in the configuration settings designer
The configuration settings designer has a value type as String but a configuration value as “https://sso.contoso.com/idpov/accesslogin/FedSSODispatch.faces?PartnerIdpId=https://sts.windows.net/{GUID}/&TargetResource=https://sso.contoso.com/idprov/pages/home/dispatch.jsp?SpName=MBF”, which has invalid characters XML format doesn’t support. Please correct it accordingly.
This error message clearly points to the presence of “invalid characters” within the configuration value, specifically citing an issue with the XML format that underlies the configuration profile. It highlights the conflict between the expected string value and the validation rules imposed by the system preparing the data for the XML profile. The administrator is prompted to correct the value, but the message itself doesn’t explicitly state which character is problematic or how to correct it in a way that satisfies the XML format requirements. This leaves the administrator troubleshooting why a standard URL string is being rejected.
The Root Cause: XML Encoding Requirements¶
The reason behind this seemingly counterintuitive error lies in the fundamental rules of XML formatting. App configuration policies for iOS devices, particularly those delivered via the Managed App Configuration channel, are structured using XML property lists (.plist files). XML has a set of characters that are reserved for its own syntax. These characters, if used directly within the content of an XML element or attribute value, can be misinterpreted by an XML parser, leading to errors in parsing the document structure itself.
The ampersand symbol (&) is one such reserved character in XML. It is specifically used to start an entity reference, which is a mechanism in XML for representing special characters or predefined text strings. For example, < represents the less-than sign (<), > represents the greater-than sign (>), and " represents a double quote ("). The ampersand itself is represented by the entity reference &.
When the Intune configuration designer is used, it takes the key-value pairs entered by the administrator and constructs the corresponding XML structure for the iOS configuration profile. The designer includes validation logic that checks if the entered values are compatible with the XML format. If a value contains a reserved XML character like the ampersand without being properly encoded, the validation fails because the raw character is not permitted within the plain text content of an XML node unless it is part of a valid entity reference.
Therefore, when the URL containing a literal ampersand is entered, the designer’s validation detects the presence of the raw & character. It recognizes that this character, if included directly in the XML output, would violate the XML specification unless it’s correctly escaped. Since the designer doesn’t automatically perform this escaping for string values entered in the GUI, it flags the value as containing “invalid characters XML format doesn’t support,” leading to the mismatch error. The error message’s reference to a “mismatch between the value type and the configuration value” is slightly misleading; it’s not a type mismatch in the programming sense (the value is indeed a string), but rather a format mismatch concerning the string’s content validity within the target XML structure. The core issue is strictly the presence of an unescaped XML reserved character.
Effective Resolutions: Addressing the Encoding Problem¶
Fortunately, resolving this issue involves standard techniques for handling special characters in XML. There are a couple of straightforward methods to provide the URL value in a format that the Intune configuration designer and the underlying XML structure can accept. These methods either avoid the problematic character altogether or ensure it’s correctly represented using XML entity encoding.
Method 1: Utilizing a Short URL or Redirect Service¶
The first method focuses on changing the configuration value itself so that it no longer contains the problematic ampersand. This can be achieved by using a URL shortening service or setting up an internal URL redirect. Instead of providing the long, complex URL with query parameters directly, the administrator configures a short URL (e.g., https://short.contoso.com/sso) that, when accessed, redirects the user’s browser or the application to the original, longer URL.
Using a short URL or a redirect service has several advantages. It simplifies the configuration value in Intune, making it shorter and less prone to errors caused by special characters. It also provides flexibility; if the target URL ever changes, the administrator only needs to update the redirect destination on the URL service side, not the Intune configuration policy itself, reducing the need for policy redeployment.
However, there are potential drawbacks. This method introduces an external dependency (the URL shortening/redirect service). If the service is unavailable or misconfigured, the SSO process might fail. Furthermore, for some security-conscious applications or environments, redirects might be audited or restricted. The application receiving the configuration might also behave differently when following a redirect compared to being given the final destination URL directly. Despite these considerations, for many scenarios, this is a simple and effective workaround that completely bypasses the XML encoding issue in Intune.
Method 2: XML Entity Encoding¶
The second method addresses the XML incompatibility directly by replacing the literal ampersand character (&) with its corresponding XML entity reference. As established earlier, the XML entity reference for the ampersand character is &. This sequence tells an XML parser that the following characters (amp;) are not part of a new entity reference but are the specific representation of a literal ampersand character that should be interpreted as data, not markup.
To implement this fix, the administrator must edit the configuration value in the Intune designer and replace every instance of a naked ampersand (&) with &. Applying this to the example URL:
Original value:
https://sso.contoso.com/idpov/accesslogin/FedSSODispatch.faces?PartnerIdpId=https://sts.windows.net/{GUID}/&TargetResource=https://sso.contoso.com/idprov/pages/home/dispatch.jsp?SpName=MBF
Value with encoded ampersand:
https://sso.contoso.com/idpov/accesslogin/FedSSODispatch.faces?PartnerIdpId=https://sts.windows.net/{GUID}/&TargetResource=https://sso.contoso.com/idprov/pages/home/dispatch.jsp?SpName=MBF
Notice that only the single ampersand separating the two query parameters (&TargetResource) is replaced. The ampersands that are part of the & escape sequence itself are not encoded recursively. Once this modification is made, the configuration value is valid from an XML perspective. When the policy is saved, the Intune designer should accept the value without the mismatch error, as it now conforms to the necessary XML encoding rules.
This method is often preferred when redirects are not feasible or desirable. It provides the application with the exact final URL. The primary drawback is that the encoded URL is less readable to humans and requires the administrator to be aware of XML encoding rules. For values that contain multiple special characters, the encoded string can become quite convoluted.
Here’s a table showing common XML/HTML entity escapes that might be relevant in other configuration scenarios:
| Character | Name | XML/HTML Entity | Purpose |
|---|---|---|---|
" |
Quotation mark | " |
Used to escape double quotes in text |
' |
Apostrophe | ' |
Used to escape single quotes (apostrophes) |
< |
Less-than sign | < |
Used when character could be start of tag |
> |
Greater-than sign | > |
Used when character could be end of tag |
& |
Ampersand | & |
Used when character could be start of entity |
Understanding these basic XML entity references is crucial for troubleshooting configuration issues that involve special characters.
Method 3: Using the XML Editor (Advanced)¶
While the original article doesn’t explicitly mention this, an alternative approach within Intune’s app configuration policy creation is to switch the “Configuration settings format” from “Use configuration designer” to “Enter XML data.” This option allows administrators to provide the entire configuration payload as raw XML.
<dict>
<key>ssoAuthEndpoint</key>
<string>https://sso.contoso.com/idpov/accesslogin/FedSSODispatch.faces?PartnerIdpId=https://sts.windows.net/{GUID}/&TargetResource=https://sso.contoso.com/idprov/pages/home/dispatch.jsp?SpName=MBF</string>
<!-- Add other configuration keys here -->
</dict>
When using the XML editor, the administrator is directly responsible for ensuring the XML is well-formed and adheres to the .plist structure expected by iOS. This includes correctly encoding any special characters within string values. By manually entering the XML, the administrator bypasses the designer’s specific validation and relies on the system’s ability to process the provided XML payload. This method requires a deeper understanding of the application’s expected configuration structure and XML formatting but offers maximum flexibility. If the designer’s validation is overly restrictive or buggy for certain complex values, the raw XML editor can serve as a powerful workaround, provided the XML syntax (including & encoding) is absolutely correct.
Broader Implications and Best Practices¶
This specific bug related to ampersands highlights a broader principle in IT configuration: the importance of understanding data formats and encoding requirements. While graphical user interfaces like the Intune configuration designer aim to simplify complex tasks, they sometimes abstract away details that become critical when dealing with non-standard input or specific technical constraints.
Handling special characters is a common challenge across various configuration scenarios, not just Intune or iOS. Whether dealing with URLs, passwords, file paths, or code snippets within configuration files (be it XML, JSON, YAML, or plain text), awareness of how different characters are interpreted is vital. Improper handling can lead to parsing errors, security vulnerabilities (like injection attacks), or simply misconfigured applications.
Best practices for IT administrators when dealing with application configurations include:
- Validate Inputs: Always test configuration values, especially those involving special characters, in a controlled environment before deploying widely.
- Understand the Underlying Format: Be aware of the data format used by the configuration system (e.g., XML for iOS profiles) and its specific encoding rules for special characters.
- Use Escaping/Encoding: When special characters are necessary within a value, use the correct escaping or encoding mechanism required by the configuration format.
- Consider Alternatives: If complex values with many special characters are problematic, explore alternative solutions like redirects, configuration files hosted externally, or simpler configuration structures if the application supports them.
- Consult Documentation: Refer to both the endpoint management system’s (Intune) documentation and the application’s documentation for specific configuration requirements and known limitations.
Deployment of Intune App Configuration Policies can be visualized with a simple flow:
mermaid
graph TD
A[Admin Creates Policy] --> B{Configuration Settings Format};
B --> C{Use Configuration Designer};
B --> D{Enter XML Data};
C --> E[Admin Adds Key/Value];
E --> F{Value Contains Special Char?};
F -- Yes --> G{Is Char Escaped Correctly?};
G -- No --> H[Designer Validation Error];
G -- Yes --> I[Policy Saved Successfully];
F -- No --> I;
D --> J[Admin Enters Raw XML];
J --> K{Is XML Valid & Encoded?};
K -- No --> L[XML Parsing Error];
K -- Yes --> I;
I --> M[Policy Deployed to Devices];
M --> N[App Reads Configuration];
N --> O{Configuration Applied};
O --> P[App Functions as Expected];
O -- Error --> Q[Application Error/Misbehavior];
This diagram illustrates how an issue at the data entry or format level (like the ampersand bug) can prevent a policy from even being saved successfully, blocking the entire deployment process.
Seeking Further Assistance¶
If the methods of using a short URL or encoding the ampersand with & do not resolve the issue, or if the specific application’s configuration requirements are complex and difficult to translate into the correct format, seeking assistance may be necessary.
For issues that appear to be platform-specific or related to how the managed configuration is interpreted by the iOS operating system or the application itself, consulting Apple Support might provide insights into how iOS handles XML property lists and special characters in configuration profiles. They may have specific requirements or known issues related to the managed app configuration channel.
If the problem seems to stem from the Intune portal’s behavior, validation, or policy deployment mechanism, contacting Microsoft Support would be the appropriate step. They can investigate potential bugs within the Intune service or provide guidance on correctly formatting the configuration within the portal.
Sometimes, the issue might be with how the application itself parses or uses the configuration value. In such cases, reaching out to the application vendor’s support team is crucial. They can confirm the expected configuration format and troubleshoot why the application might not be correctly interpreting the value received via managed configuration, even if it appears correct in Intune.
Supporting media can also be helpful resources when troubleshooting such issues. While the original article doesn’t link specific videos, searching platforms like YouTube for tutorials on “Intune app configuration,” “iOS managed app configuration,” or “XML character encoding” can provide valuable visual guides and explanations. For instance, a hypothetical video titled “Troubleshooting Intune App Configuration Policies” could cover common pitfalls like this ampersand issue.
(Note: This is a placeholder; replace example_video_id with a real YouTube video ID if a relevant video exists.)
Such resources can supplement official documentation and provide practical demonstrations of policy creation and troubleshooting steps.
Important Considerations and Disclaimers¶
When implementing solutions involving external services (like URL shorteners) or interacting with third-party vendors (like Apple or application developers), it’s important to be mindful of dependencies and support boundaries.
The third-party products or services discussed in the context of potential solutions (like URL shortening services or the Apple platform itself) are developed and maintained by companies independent of Microsoft. Microsoft provides information about these solutions as potential workarounds but does not guarantee the performance, reliability, or security of these third-party offerings. Administrators should perform their own due diligence before integrating external services into their managed environment.
Similarly, contact information for third parties like Apple Support is provided for informational purposes to help administrators find additional resources. This contact information is subject to change without notice. Microsoft does not guarantee the accuracy or continued availability of third-party contact details.
The core technical explanation regarding XML encoding is standard across the XML specification, but the specific behavior of the Intune configuration designer concerning validation and encoding of string inputs can be specific to the Intune service and its implementation details.
By understanding the root cause – the incompatibility of the raw ampersand character with the underlying XML format – and applying the appropriate resolution, administrators can successfully configure applications in Intune even when complex values like URLs with query parameters are required. Whether choosing to simplify the value via redirection or correctly encoding the special character, addressing the XML requirement is key to overcoming the “mismatch error” in the configuration designer.
Have you encountered similar issues with special characters in Intune or other configuration systems? Share your experiences or alternative solutions in the comments below!
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