security - What bad things can a user do in a browser without the script tag? -

-

I have an entry form where the user can type in arbitrary HTML, except for the script tag, what I need to filter is? Here's what I do: 

  userInput.replace (/ & lt; (script) / GI, "& amp; $ 1");   
 but manages a white list of tags (used here at SO), and filters all other tags (spaces). Why?  
 I do not like white lists because I do not want to stop the user from entering the arbitrary tag, if he chooses; But I can use a more comprehensive blacklist in addition to 'script', what if I need to do as a black list?   
 
 
 short answer: they can do anything  with   Script  tag  
 Javascript does not require a  script  tag, the script can be placed in the  almost every  HTML tag script in many places the script tag Can appear in addition to the  src  and  href  attribute, and  style  attribute used for the URL.  
 The ability to put unwanted scripts in a user on their page is a security vulnerability known as. Read around and read this topic.  
 You do not want users to add HTML to your pages. If you need this feature, consider other formats like Markdown that allow you to disable the use of any embedded HTML; Or using some other less secure option is to use a filtering library that attempts to remove all the scripts, such as HTMLPurifier, if you choose the filtering option, subscribe to the announcements of the new release and always use the new projects Go back to your project and work around to install a bug-fixed release of filters.

Comments

Post a Comment

Popular posts from this blog

mysql - BLOB/TEXT column 'value' used in key specification without a key length -

-
I have developed an extension which works up to 1.6 on Magren (I'm trying Enterprise Edition, And I think the community is the same problem, because it is the same code). In my install script, I see the $ installer-> gt; CreateEntityTables ($ this- & gt; getTable ('alphanum / info')); The installation is done until it is not in the _text unit table. It crashed there! It turns out that when I log in to SQL and run it via PHPmyadmin, then this error is: Blob / Text column 'value' is used without the key 'key' . I saw the code there, and this is what is trying to create an index on the value column: -> addIndex ($ this- & gt; getIdxName ($ eavTableName, array ( 'attribute_id array (' attribute_id ',' value ')) - & gt; addIndex ($ this- & gt; getIdxName ($ eavTableName, array (' entity_type_id ' , 'Value')), array ('entity_type_id', 'value')) If there is no if statement is n...
Read more

c# - Using Vici cool Storage with monodroid -

-
Oh, for the moment I am not sure how it is officially supported, but for the success of the people Using Monodroid Vic Cool Storage I am able to leave and compile assemblies in my project, but while trying to use some classes, the errors of time have to be gathered. Especially when trying to connect like the example for Mono Touch string dbName = path. Cobain (environment. Gatefolder path (environment specialfolder personal), "mydb.db3"); // The following line will be called coolestation, where is the database, // to make it if it does not exist, and call a delegate that creates the necessary tables (only when the database file was newly created //) CSConfig.SetDB (DbName, true, () => {CSDatabase.ExecuteNonQuery ("Subscriber Integer Primary Key Attribute, Name Text (50) No, Number, Date First Text (30)");); There is no difference when I try to use the methods of CSConfig and when I cscfif If I try to pass 3 aggregates to STDB (3) then I get the invalid ...
Read more

python - referencing a variable in another function? -

-
I am an experienced TCL developer and write my own processes to help myself. I call it a proc i callVar, print out the value of the variable in a certain format, so I know that it is variable and what is the value "set foo 1; putVar foo" result 'foo = "1" I want to do the same thing in Python, but I can not find the answer :( In TCL I use the up command because when I pass the name of the variable, then I can see the value at the top. . I understand that an advanced light in the dragon There is no mechanism of r, but with its introspection capability, I would think that this is something trivial, but I am not getting the answer anywhere. It seems that this should work: and expanded: def foo (): y = "Hello World" printwor ("y") foo () y = "Hello World " You can, but you should not do so if your code is correct If is needed , then there is something wrong with your design, and you should probably use the dictionar...
Read more