Java script obfuscation code#

This opens the door for people to possibly reverse engineer the app.ĭevelopers usually use obfuscation in the source code of an application if parts of that code are exposed to the general public. In web browsers, it is possible to view the source code of a web page after it has been rendered, and if your code is not protected then it is easy for a user to copy that code and see what your web application is doing. There are legitimate, non-malicious reasons for wanting to use a JavaScript obfuscator, especially if you’re client-side. The result is that much of the data cannot be analyzed without first rendering the page and then debugging it. This makes it very difficult for the intent of the script to be known because it is handling the data, looping it into functions that will eventually generate the page data that the victim will see. These arrays contain the encrypted content of the final page to be rendered, the decoded JavaScript function that is responsible for decryption of the first payload and the JavaScript code keywords such as ‘push’ and ‘shift’ that will be used by other functions on the original page.” Katz explains, “ The page code contains two payload arrays, flagged as sections one (1) and four (4) in the image. An anonymous JavaScript function then performs additional operations on the second payload, hands it over to the sixth piece of code and then finally the code is executed. The third snippet of code then retrieves the first payload’s values, and then a second payload is generated. A payload array is generated, then passed on to another segment of code where a function shuffles all of the payload data. In an example piece of code, Kats highlighted the seven different elements of code used in an obfuscation attack. This method is useful only to a point, however, because the information of the malicious payload is normally only revealed upon the page being rendered. Similar methods could be used to thwart email attacks but this is not widely adopted at this stage, as seen in the rise of attacks that use this delivery method. Some countermeasures can be used to help detect malicious JavaScript code in websites, such as String Pattern Analysis.

Variables are named to be more confusing, comments are removed, data structures are changed and functions are introduced that confuse and change data. Obfuscation in programming and coding means that all of the code in an application is reworked to make it difficult, or impossible, to understand.

Methods used for obfuscationĪs most people already know, content escaping is a big factor in these attacks as a means of obfuscation. This means that it is far more difficult to detect any malicious code up until the asset has been rendered. This page has been generated by the malicious code embedded in the email. This means that once the script has run on a target computer, the user or victim will essentially be feeding their personal information into a local page. There are a few reasons why these kinds of attacks have suddenly become popular, primarily because JavaScript is a client-side scripting language. HEX encoding variable name obfuscation, 86%.Content escaping obfuscation techniques, 72%.The following shows the attack types and increases from the report:

Java script obfuscation