Microsoft Dynamics Ax Writing Secure X++ Code

Microsoft Dynamics AX 4.0


Writing Secure X++ Code


White Paper


[Security and Trustworthy Computing]




















Date: June 12, 2006

Michael Fruergaard Pontoppidan
Mukkul Dasgupta













This is a preliminary document and may be changed substantially prior to finalcommercial release of the software described herein.

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Table of Contents

Introduction 5
Kernel APIs 5
Dangerous Code Patterns in X++ 5
Recommended Approach for Updating Legacy Code 5

Credentials and Cryptography 7

Dynamics AX Code Access Security 8
Implementing Code Access Security 8
API Owner 8
API Consumer 8
UserImpersonation API 9
Mitigation 9
New Best Practice Rules 10
Direct SQL 10
Mitigation 11
New Best Practice Rules 11
Run-time Compilation and Execution of X++ 11
Mitigation 11
New Best Practice Rules 12
Data-controlled Execution of X++ 12
Mitigation 12
New Best Practice Rules 13
Files 13
Mitigation 14
New Best Practice Rules 14
Win32 Interop 15Mitigation 15
New Best Practice Rules 15
Using Managed Assemblies 16
WinAPI 16
Mitigation 17
New Best Practice Rules 17

Server-bound Batch Processing 18
Provisioning Legacy Batch-enabled X++ Classes 18
Checking for Unsupported AX Client Interactions 19
Enabling a Class to Run as a Server-bound Batch Job 19
Classes in Batch Journals 19

Tighter Privileges on APIs20
Modifying X++ and Metadata 20
Mitigation 20
APIs with Enforced Authorization Checks 20
APIs that are Turned Off by Default 20

Data Authorization 21
Access to System Tables (Table Permission Framework) 21
AOSAuthorization Property 21
AOSValidate Functions 22
Record-level Security 22
Using Display and Edit methods 22
Using a ListView, TreeView, or Table to...