angular vulnerabilities

• Vulnerable module: angular
• Introduced through: angular@1.6.8

Detailed paths

• Introduced through: angular@1.6.8

Overview

angularjs is a toolset for building the framework suited to your application development.

Affected versions of this package are vulnerable to Cross-site Scripting (XSS) through SVG files if enableSvg is set.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.6.9 or higher.

References

• GitHub angular ChangeLog

• Vulnerable module: angular
• Introduced through: angular@1.6.6

Detailed paths

• Introduced through: angular@1.6.6

Overview

angular is an HTML enhanced for web apps.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) via ideographic space chararcters in URIs.

Browsers mutate attributes values such as 　javascript:alert(1) when they are written to the DOM via innerHTML in various vendor specific ways. In Chrome (<62), this mutation removed the preceding "whitespace" resulting in a value that could end up being executed as JavaScript.

Here is an example of what could happen:

// Code goes here
var h1 = document.querySelector('h1');
h1.innerHTML = '<a href="&#x3000;javascript:alert(1)">CLICKME</a>';
var innerHTML = h1.innerHTML;
console.log(innerHTML);
h1.innerHTML = innerHTML;

The sanitizer contains a bit of code that triggers this mutation on an inert piece of DOM, before angular sanitizes it.

Note: Chrome 62 does not appear to mutate this particular string any more, instead it just leaves the "whitespace" in place. This probably means that Chrome 62 is no longer vulnerable to this specific attack vector.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.6.7 or higher.

References

• GitHub PR
• GitHub Issue
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.6.0

Detailed paths

• Introduced through: angular@1.6.0

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to JSONP Callbacks attacks.

JSONP (JSON with padding) is a method used to request data from a server residing in a different domain than the client.

Any url could perform JSONP requests, allowing full access to the browser and the JavaScript context. This can lead to Cross-site Scripting.

Remediation

Upgrade angular to version 1.6.1 or higher.

References

• GitHub Issue
• GitHub PR 1
• GitHub PR 2

• Vulnerable module: angular
• Introduced through: angular@1.5.8

Detailed paths

• Introduced through: angular@1.5.8

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to CSP Bypass. Extension URIs (resource://...) bypass Content-Security-Policy in Chrome and Firefox and can always be loaded. Now if a site already has a XSS bug, and uses CSP to protect itself, but the user has an extension installed that uses Angular, an attacker can load Angular from the extension, and Angular's auto-bootstrapping can be used to bypass the victim site's CSP protection.

Remediation

Upgrade angular to version 1.5.9 or higher.

References

• GitHub Pr
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.5.0-rc.1

Detailed paths

• Introduced through: angular@1.5.0-rc.1

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) due to the usemap attribute not being blacklisted.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.5.0-rc.2 or higher.

References

• Changelog
• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.5.0-beta.2

Detailed paths

• Introduced through: angular@1.5.0-beta.2

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) via the SVG <use> element. The <use> element can reference external SVG's (same origin) and can include xlink:href javascript urls or foreign object that can execute XSS. The change disallows <use> elements in sanitized SVG markup.

An example of a malicious SVG document would be:

SVG to sanitize:

<svg><use xlink:href="test.svg#xss" /></svg>

External SVG file (test.svg):

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg" width="100"
   height="100"
   id="xss">
<a xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="javascript:alert(1)">
  <circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" />
</a>
</svg>

Here the SVG to sanitize loads in the test.svg file via the <use> element. The sanitizer is not able to parse this file, which contains malicious executable mark-up. This can only be taken advantage of if the external file is available via the same origin restrictions in place.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.5.0-rc.0 or higher.

References

• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.4.14

Detailed paths

• Introduced through: angular@1.4.14

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Clickjacking. By enabling the SVG setting without taking other precautions, you might expose your application to click-hijacking attacks. In these attacks, sanitized SVG elements could be positioned outside of the containing element and be rendered over other elements on the page (e.g. a login link). Such behavior can then result in phishing incidents.

To protect against these, explicitly setup overflow: hidden css rule for all potential SVG tags within the sanitized content:

.rootOfTheIncludedContent svg {
  overflow: hidden !important;
}

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.5.0-beta.2 or higher.

References

• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.4.9

Detailed paths

• Introduced through: angular@1.4.9

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks involving assignment on constructor properties.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.4.10 or higher.

References

• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.3.1

Detailed paths

• Introduced through: angular@1.3.1

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Command Injection due to the assignment functions accessing constructors functions, allowing attackers to execute their malicious code.

Remediation

Upgrade angular to version 1.3.2 or higher.

References

• GitHub Commit
• Change log

• Vulnerable module: angular
• Introduced through: angular@1.2.32

Detailed paths

• Introduced through: angular@1.2.32

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) due to unsanitized URIs in ng-srcset.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.3.0-rc.4 or higher.

References

• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.2.29

Detailed paths

• Introduced through: angular@1.2.29

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Script Injection.

Details

link[href] attributes were not protected via $sce, which prevents interpolated values that fail the RESOURCE_URL context tests from being used in interpolation. For example if the application is running at https://docs.angularjs.org then the following will fail:

<link href="{{ 'http://mydomain.org/unsafe.css' }}" rel="stylesheet">

By default, RESOURCE_URL safe URLs are only allowed from the same domain and protocol as the application document.

Remediation

Upgrade angular to version 1.2.30 or higher.

References

• GitHub Changelog
• GitHub PR
• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.1.5

Detailed paths

• Introduced through: angular@1.1.5

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks.

DOM event handlers await events to occur (e.g. onclick, onkeypress, etc) and execute arbitrary Javascript code in accordance to the event. By default, interpolations inside DOM event handlers are disallowed. Using an interpolation for such handlers means that the interpolated value is a JS string being evaluated. Storing or generating such strings is error prone and likely leads to a Cross-site Scripting (XSS) vulnerability if you're not careful. On the other hand, ng-click and such event handlers evaluate Angular expressions that are a lot safer (e.g. No direct access to global objects - only scope), cleaner and harder to exploit.

To migrate the code follow the example below: Before:

JS:   scope.foo = 'alert(1)';

HTML: <div onclick="{{foo}}">

After:

JS:   scope.foo = function() { alert(1); }

HTML: <div ng-click="foo()">

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.2.0 or higher.

References

• GitHub Commit

• Vulnerable module: angular
• Introduced through: angular@1.1.5

Detailed paths

• Introduced through: angular@1.1.5

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS).

Concatenating expressions makes it hard to reason about whether some combination of concatenated values are unsafe to use and could easily lead to XSS. By requiring that a single expression be used for *[src/ng-src] such as iframe[src], object[src], etc. (but not img[src/ng-src] since that value is sanitized), it is ensured that the value that's used is assigned or constructed by some JS code somewhere that is more testable or make it obvious that you bound the value to some user controlled value. This helps reduce the load when auditing for XSS issues.

To migrate your code, follow the example below:

Before:

JS:
scope.baseUrl = 'page';
scope.a = 1;
scope.b = 2;

HTML:
<!-- Are a and b properly escaped here? Is baseUrl
 controlled by user? -->
<iframe src="{{baseUrl}}?a={{a}&b={{b}}">

After:

JS:
var baseUrl = "page";
scope.getIframeSrc = function() {
  // There are obviously better ways to do this.  The
  // key point is that one will think about this and do
  // it the right way.
  var qs = ["a", "b"].map(function(value, name) {
  return encodeURIComponent(name) + "=" +
 encodeURIComponent(value);
}).join("&");
  // baseUrl isn't on scope so it isn't bound to a user
  // controlled value.
  return baseUrl + "?" + qs;
}

HTML: <iframe src="{{getIframeSrc()}}">Before:

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Remediation

Upgrade angular to version 1.2.0 or higher.

References

• GitHub PR
• GitHub Commit

• Vulnerable module: connect
• Introduced through: express@2.5.11 and express@2.5.10

Detailed paths

• Introduced through: hapi@0.0.4 > express@2.5.11 > connect@1.9.2
• Introduced through: angular@0.0.4 > express@2.5.10 > connect@1.9.2

Overview

connect is a high performance middleware framework.

Affected versions of the package are vulnerable to Denial of Service (DoS) attacks. It is possible to crash the node server by requesting a url with a trailing backslash in the end.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade connect to version 2.0.0 or higher.

References

• GitHub Issue
• GitHub Commit

• Vulnerable module: express
• Introduced through: express@3.0.6, express@2.5.11 and others

Detailed paths

• Introduced through: cordova@0.0.4 > express@3.0.6
• Introduced through: hapi@0.0.4 > express@2.5.11
• Introduced through: angular@0.0.4 > express@2.5.10

Overview

express is a minimalist web framework.

Affected versions of this package do not enforce the user's browser to set a specific charset in the content-type header while displaying 400 level response messages. This could be used by remote attackers to perform a cross-site scripting attack, by using non-standard encodings like UTF-7.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Recommendations

Update express to 3.11.0, 4.5.0 or higher.

References

• GitHub release 3.11.0
• GitHub release 4.5.0

• Vulnerable module: connect
• Introduced through: express@3.0.6, express@2.5.11 and others

Detailed paths

• Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2
• Introduced through: hapi@0.0.4 > express@2.5.11 > connect@1.9.2
• Introduced through: angular@0.0.4 > express@2.5.10 > connect@1.9.2

Overview

Connect is a stack of middleware that is executed in order in each request.

The "methodOverride" middleware allows the http post to override the method of the request with the value of the _method post key or with the header "x-http-method-override".

Because the user post input was not checked, req.method could contain any kind of value. Because the req.method did not match any common method VERB, connect answered with a 404 page containing the "Cannot [method] [url]" content. The method was not properly encoded for output in the browser.

Source: Node Security Project

Example

~ curl "localhost:3000" -d "_method=<script src=http://nodesecurity.io/xss.js></script>"
Cannot <SCRIPT SRC=HTTP://NODESECURITY.IO/XSS.JS></SCRIPT> /

Mitigation factors

Update to the newest version of Connect or disable methodOverride. It is not possible to avoid the vulnerability if you have enabled this middleware in the top of your stack.

History

• (2013-06-27) Bug reported
• (2013-06-27) First fix: escape req.method output
• (2013-06-27) Second fix: whitelist

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like \< > \" \' are not escaped properly.

There are a few types of XSS:

• Persistent XSS is an attack in which the malicious code persists into the web app’s database.
• Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
• DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

• Vulnerable module: qs
• Introduced through: express@3.0.6, express@2.5.11 and others

Detailed paths

• Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2 > qs@0.5.1
• Introduced through: hapi@0.0.4 > express@2.5.11 > qs@0.4.2
• Introduced through: angular@0.0.4 > express@2.5.10 > qs@0.4.2

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

Affected versions of this package are vulnerable to Denial of Service (DoS). When parsing a string representing a deeply nested object, qs will block the event loop for long periods of time. Such a delay may hold up the server's resources, keeping it from processing other requests in the meantime, thus enabling a Denial-of-Service attack.

Remediation

Update qs to version 1.0.0 or higher. In these versions, qs enforces a max object depth (along with other limits), limiting the event loop length and thus preventing such an attack.

References

• Node Security Advisory