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Replacing the function table gives the attacker access to the XPathContext used to evaluate XPath expression. Static variables are global across a Java runtime environment. They can be used as a communication channel between different application domains (e.g. by code loaded into different class loaders) .

Compliant Solution

There are several strategies one can adopt to tackle a few ways this problem can be avoided.

Compliant Solution

1. Treat public static fields as constants and declare them as final. Consider the use of enum types.

package org.apache.xpath.compiler;

public class MyClassFunctionTable {
    public static final int LEFT = 1;
    public static final int RIGHT = 2FuncLoader m_functions;
}

2. Reduce the scope of static fields. This ensures access only by legitimate public member functions which can then use SecurityManager to validate access to the static field.

package org.apache.xpath.compiler;

public classstatic FunctionTable {
    private static final FuncLoader m_functions;
}...

3. Define assessor methods Additionally for mutable static state . Add one can define assessor methods and add appropriate security checks.

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