CS.SV.TRANSP.ASSEMBLY_LOAD

Transparent code should not load assemblies from byte arrays.

The security review for transparent code is not as thorough as the security review for critical code, because transparent code cannot perform security sensitive actions. Assemblies loaded from a byte array might not be noticed in transparent code, and that byte array might contain critical, or more importantly safe-critical code, that does need to be audited. Therefore, transparent code should not load assemblies from a byte array.

Mitigation and prevention

To fix a violation of this rule, mark the method that is loading the assembly with the SecurityCriticalAttribute or the SecuritySafeCriticalAttribute attribute.

Vulnerable code example

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  using System;
  using System.IO;
  using System.Reflection;
  
  namespace TransparencyWarningsDemo
  {
  
      public class TransparentMethodsLoadAssembliesFromByteArraysClass
     {
         public void TransparentMethod()
         {
             byte[] assemblyBytes = File.ReadAllBytes("DependentAssembly.dll");
 
             // CA2144 violation - transparent code loading an assembly via byte array.  The fix here is to 
             // either make TransparentMethod critical or safe-critical.
             Assembly dependent = Assembly.Load(assemblyBytes);
         }
     }
 }

The rule fires on the code because a transparent method loads an assembly from a byte array.