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What is Cross-Frame Scripting (XFS)?


More than the vast majority of the 4 subject connections and areas are powerless against XFS and XSS assaults, as per ongoing exploration by Singaporean security master Wang Jing.

When joined with social designing, an aggressor might have the option to block keystrokes. We should take a gander at why XFS assaults exist, how they vary from XSS assaults, and see a format string attack example.

What is Cross-Frame Scripting (XFS)?

Cross-Frame Scripting (XFS) definition

Whenever a casualty is fooled into visiting a noxious site through his browser, a Cross Frame Scripting assault happens. In the HTML outline, the pernicious assailant who controls this page stacks an outsider page. The casualty's keystrokes are then recorded by a vindictive JavaScript keylogger and shipped off the aggressor's server.

XFS attack in action

At the point when a program client visits a site page constrained by the assailant in a XFS assault, the accompanying occurs:

  • A HTML IFRAME component is utilized to open the genuine page (typically a login page).
  • The IFRAME component is extended to fill the whole page, and the casing's boundaries are taken out, giving the feeling that the client is on a real site.
  • Malevolent JavaScript outside the IFRAME catches console occasions (keystrokes) and sends them to the aggressor when the casualty attempts to sign in to an authentic site or web application.

Because of the Same-Origin Policy, this is preposterous in many programs. This approach, which is upheld by all cutting-edge programs, keeps data from being divided among destinations with various beginnings by means of JavaScript. Since the assailant-controlled page and the authentic site or web application are facilitated on independent servers, JavaScript on the aggressor's server ought not be ready to get to key occasions from the IFRAME component containing the outsider page.

XFS attack in action
XFS attack in action

Cross-Frame Scripting vs. Cross-Site Scripting

We should clear up the naming disarray before we dive into the specialized subtleties. Cross-frame scripting isn't equivalent to cross-site prearranging, notwithstanding the comparable name (XSS). There is a ton of questionable or misdirecting data on the web, remembering for the OWASP site, so honestly:

  • Cross-Site Scripting (XSS) is the point at which an aggressor infuses noxious JavaScript into a weak site (which doesn't need to be constrained by the assailant).
  • Sneaking around on the client in the wake of fooling them into visiting a noxious site that contains an iframe with a real page is known as cross-frame scripting (XFS).

The two can, be that as it may, be joined assuming the inserted page is helpless against a XSS assault.

Conditions for performing an attack

Cross-frame scripting ought not be imaginable under ordinary conditions because of the equivalent beginning strategy, which expresses, that contents shouldn't approach pages stacked from various servers, including admittance to their occasions. This implies that regardless of whether an aggressor prevailed with regards to hoodwinking the client into visiting an outlined site, the noxious JavaScript on the encompassing page would not be able to keep an eye on the client's activities inside the implanted edge.

Explicit program bugs, then again, may permit a parent edge to get to a youngster outline stacked from an alternate source. The assailant can sneak around on the client's activities assuming a weak program adaptation is utilized to open an uncommonly pre-arranged pernicious site (regularly subsequent to clicking a phishing join). All of the accompanying should be valid for a XFS assault to find success:

  1. A vindictive URL is shipped off the client, who opens it.
  2. The equivalent beginning strategy execution in the client's program is broken.
  3. The client is captivated by an authentic site that permits itself to be installed in an iframe.

It is exceptionally far-fetched that each of the three circumstances will be met in this day and age. While clients are as yet ready to tap on phishing joins, finding somebody who utilizes a program with a bug (like a few variants of Internet Explorer) would be troublesome. It is likewise normal practice these days to try not to stack sites in outlines. When it's all said and done, is a moderately minor web application security danger.

What does a Cross-Frame Scripting attack entail?

Cross Frame Scripting assaults can lead to the accompanying issues:

  • Robbery of individual data and character
  • Somewhat controlling the casualty's PC
  • Spyware is introduced on PCs and organizations in anticipation of future sniffing.
  • Denial of Service (DoS) assaults are sent off against different sites.
  • Clickjacking is done utilizing the noticeable casing.

Protecting applications from cross-frame scripting

Web application engineers can forestall outline inserting on the grounds that Cross-Frame Scripting weaknesses show up in internet browsers. There are three primary strategies for protection. Since they're totally used to safeguard against clickjacking, we've composed an article about them: How to Defend Against Clickjacking Attacks:

  • Framebusting requires just a change to the HTML code of the site page.
  • Security Policy for Content: outline predecessors header: The genuine site proprietor should change the web server arrangement to have this header show up on each page naturally.
  • The X-Frame-Options header: The real site proprietor should change the web server arrangement so this header is incorporated with each page naturally.

How can Wallarm help?

Wallarm is dependably really smart to check your websites since it gives best-practice proposals in the event that it sees as absent or misconfigured HTTP headers, like outlining controls. To decrease the gamble of basic bugs, you ought to constantly utilize a cutting-edge program and stay up with the latest. Like that, you can have confidence that even something however essential as the equivalent beginning approach seems to be constantly followed. Integrate Wallarm products into your business: API Security Platform or Cloud WAF.



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February 26, 2024
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