Is the employment of "javascript:" in Angular 2+ considered risky?

Question

Is the employment of "javascript:" in Angular 2+ considered risky?

According to the guidelines provided in the Angular security guide, it is crucial to prevent malicious code from infiltrating the DOM (Document Object Model) in order to thwart XSS attacks. Attackers may attempt to insert harmful elements like tags into the DOM, which can lead to unauthorized code execution on your website. The risk extends beyond just tags, as various elements and properties within the DOM provide avenues for malicious code execution, such as <img onerror="..."> and <a href="javascript:...">. Allowing attacker-controlled data into the DOM significantly increases the likelihood of security vulnerabilities.

Sometimes, I have utilized

<a href="javascript:" (click)="someFunction()">link</a>

to style elements using CSS selectors (a:link) without the link referencing a specific URI, anchor, or executing any scripts. However, does this approach pose a threat? The potential risks associated with this practice are not explicitly outlined.

This leads to a dilemma addressed in my query on Stack Overflow: how can I ensure a consistent look for all links, including those using HREFs and JavaScript bindings, within a navigation menu while adhering to best practices?

javascript html css angular security

Answer 1

Answer №1

Consider including an empty href attribute for links with the (click) event listener

<a (click)="action()" href>Previous</a>

If this method does not yield the desired result, you can attempt the following alternatives:

<a href (click)="doSomething(); $event.preventDefault()">Link</a>
<a href (click)="!!doSomething()">Link</a>
<a href (click)="doSomething(); false">Link</a>

Answer 2

Consider including an empty href attribute for links with the (click) event listener

<a (click)="action()" href>Previous</a>

If this method does not yield the desired result, you can attempt the following alternatives:

<a href (click)="doSomething(); $event.preventDefault()">Link</a>
<a href (click)="!!doSomething()">Link</a>
<a href (click)="doSomething(); false">Link</a>

Answer 3

Answer №2

Keep up the good work.

Here is an example:

<a href="javascript:" (click)="someFunction()">link</a>

...is not posing an immediate security threat as no templateization is involved in your href.

On the other hand, consider this:

<a href="javascript:{{someVariable}}" (click)="someFunction()">link</a>

...represents a security risk because user-entered values stored in someVariable could include malicious code that would then be executed upon clicking.

Instead of using href="javascript:", opt for Angular's (click) event and apply preventDefault() to hinder the behavior you described.

<a (click)="doSomething($event)"><a/>

doSomething(event: any) {
    event.preventDefault();
}

Update

It is advised by Scott Marcus to avoid employing an a element due to the need for additional steps like preventDefault(). In such cases, it's best to utilize a span.

Implement it as follows:

<span (click)="doSomething()"></span>

Answer 4

Keep up the good work.

Here is an example:

<a href="javascript:" (click)="someFunction()">link</a>

...is not posing an immediate security threat as no templateization is involved in your href.

On the other hand, consider this:

<a href="javascript:{{someVariable}}" (click)="someFunction()">link</a>

...represents a security risk because user-entered values stored in someVariable could include malicious code that would then be executed upon clicking.

Instead of using href="javascript:", opt for Angular's (click) event and apply preventDefault() to hinder the behavior you described.

<a (click)="doSomething($event)"><a/>

doSomething(event: any) {
    event.preventDefault();
}

Update

It is advised by Scott Marcus to avoid employing an a element due to the need for additional steps like preventDefault(). In such cases, it's best to utilize a span.

Implement it as follows:

<span (click)="doSomething()"></span>

Is the employment of "javascript:" in Angular 2+ considered risky?

Answer №1

Answer №2

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