[jira] Commented: (WW-3264) Vulnerability of dynamic method invocation

["Maurizio Cucchiara (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/WW-3264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12977235#action_12977235 ] 

Maurizio Cucchiara commented on WW-3264:
----------------------------------------

It is a good idea and it should not be difficult to implement . I'd prefer the comma separated list, for consistence's reasons (as John told). 

But I'm concerned about the method attribute of action tag. None of the above examples take it in consideration. 
I'm inclined to think that s2 should "whitelist" automatically the method parameter which is defined inside action tag (alternately it should include "execute" method by default).  
But what should happen in the following case:

[...]
<action name="login" class="actions.LoginAction" method="execute"> 
        <result>/login.jsp</result> 
        <allowedMethods>doLogin</allowedMethods> 
[...]


Any thought?

> Vulnerability of dynamic method invocation
> ------------------------------------------
>
>                 Key: WW-3264
>                 URL: https://issues.apache.org/jira/browse/WW-3264
>             Project: Struts 2
>          Issue Type: Bug
>    Affects Versions: 2.1.8
>            Reporter: Alex Siman
>            Priority: Critical
>             Fix For: 2.2.x
>
>
> Dynamic method invocation is the security hole. If some of action methods has "public" visibility and return String, then attacker can call this method. In the example below, attacker can call method "changeAdminPassword()" of TestAction from URL like:
> http://example.com/test!changeAdminPassword.action
> public class TestAction
> {
>     private String currentPassword = null;
>     @SkipValidation
>     public String execute() throws Exception
>     {
>         if (getValidCurrentPassword().equals(currentPassword))
>         {
>             String feedback = changeAdminPassword();
>             addActionMessage(feedback);
>             return SUCCESS;
>         }
>         else
>         {
>             addFieldError("currentPassword", "Invalid password.");
>             return INPUT;
>         }
>     }
>     // Note "public" visibility here.
>     public String changeAdminPassword()
>     {
>         String newPassword = "new-admin";
>         // Persist changes here...
>         return "Admin password has been changed to '" + newPassword + "'.";
>     }
>     
>     public String getCurrentPassword()
>     {
>         return currentPassword;
>     }
>     public void setCurrentPassword(String currentPassword)
>     {
>         this.currentPassword = currentPassword;
>     }
> }
> To fix this vulnerability we must leverage the [com.opensymphony.xwork2.config.entities.ActionConfig.allowedMethods].
> And to prevent backward incompatibility add new default setting like:
> default.properties
> ==================
> ## Note "false".
> struts.enable.DynamicMethodInvocation.restrictToAllowedMethods = false
> Desired code in struts.xml
> ==========================
> <package name="testPackage">
>     <action name="login" class="actions.LoginAction">
>         <result>/login.jsp</result>
>         <allowedMethods>
>             <allowedMethod>doLogin</allowedMethod>
>         </allowedMethods>
>     </action>
>     <allowedMethods class="actions.LoginAction">
>         <allowedMethod>doLogin</allowedMethod>
>         <allowedMethod>doRegister</allowedMethod>
>     </allowedMethods>
>     <!— Or use <method>? -->
>     <allowedMethods class="actions.UserAction">
>         <method>create</method>
>         <method>list</method>
>         <method>view</method>
>         <!-- ... -->
>     </allowedMethods>
> </package>
> Desired code w/ Convention plugin:
> (Note @AllowedMethod anno)
> ==================================
> class LoginAction 
> {
>     @SkipValidation
>     public String execute()
>     {
>         // Nothing.
>         return INPUT;
>     }
>     @AllowedMethod
>     public String doLogin()
>     {
>         // Method's body here...
>         // password = getPasswordHash();
>         return SUCCESS;
>     }
>     // This method cannot be invoked dynamically.
>     public String getPasswordHash()
>     {
>         // Method's body here...
>         return "xxx";
>     }
> }

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.