Web Browser-Based Attacks – Types, Examples, and Prevention

Web browsers are now essential for any business, offering a convenient window to websites and a single platform for accessing content. However, this convenience comes at the cost of browser security.

95% of undetectable malware is spread through web browsing. Even more alarming is that browse-borne malware costs organizations an average of $ 3.2M.

So, how do you protect your end-users from these attacks? 

What is a Web Browser-Based Attack?

A web browser attack targets vulnerabilities in web browsers to compromise user data or execute malicious code.

These attacks also target vulnerabilities within web applications accessed via web browsers. They exploit weaknesses in the code, design, or functionality of web applications to compromise user data, steal sensitive information, or disrupt services.

They leverage the inherently open and interactive nature of web browsers to execute malicious code or manipulate user interactions.

To achieve this,

• Attackers may target your organization’s website and its end-users. For example, the Magecart attack focuses on skimming user data from forms on websites.
• Attackers may leverage the website’s execution to target its end users. Consider clickjacking and malicious pop-ups.  Here the attackers inject malicious code into the website. And the end-user systems will direct sensitive data to attackers.

Why do Browser-Based Attacks happen? 

Browser-based attacks occur due to various factors, including vulnerabilities in web browsers and web technologies, malicious actions by attackers, and lapses in security practices. Here are some reasons why browser-based attacks happen:

Technical Vulnerabilities: Flaws in browsers, plugins, and web applications provide entry points for attackers to exploit.

Security Exploitation: Attackers actively seek and capitalize on weaknesses like XSS, CSRF, and injection attacks to compromise systems.

Insecure Web Practices: Poor coding, lax security measures, and inadequate validation create vulnerabilities ripe for exploitation.

User Ignorance: Lack of awareness about threats and safe browsing practices makes users vulnerable to manipulation.

Software Neglect: Failure to update browsers, plugins, and systems leaves known vulnerabilities unpatched, and easy targets for attackers.

Third-party Risks: Dependencies on external scripts and services introduce additional attack vectors.

Financial Motivation: Attackers engage in activities like data theft, fraud, and ransomware for financial gain.

10 Common Web Browser Based Attacks

1. Cross-Site Scripting (XSS)

XSS occurs when an attacker injects malicious scripts, usually JavaScript, into web pages viewed by other users. These scripts execute in the context of the victim’s browser, allowing the attacker to steal cookies, session tokens, or other sensitive information, deface websites, or redirect users to malicious sites.

Example: Consider a blog website that allows users to leave comments. An attacker could submit a comment containing a malicious script that, when viewed by other users, steals their session cookies. When those users’ browsers send the cookies to the server, the attacker intercepts them, gaining unauthorized access to their accounts. Take a look at our comprehensive guide on robust measures to prevent XSS.

2. Cross-Site Request Forgery (CSRF)

CSRF attacks exploit the trust a website has in a user’s browser by tricking users into unknowingly executing unwanted actions on a web application in which they are authenticated. The attacker crafts a malicious request and tricks the victim into triggering it, often through social engineering techniques.

Example: An attacker sends a victim an email containing a link to a malicious website. Upon visiting the site, the victim’s browser executes a hidden request to a legitimate site where the victim is already logged in (e.g., a bank). This request transfers funds from the victim’s account to the attacker’s account without the victim’s knowledge.

3. Phishing

Phishing attacks involve masquerading as a trustworthy entity to trick users into providing sensitive information such as usernames, passwords, or credit card details. Attackers typically use email, instant messages, or fake websites to deceive victims.

Example: An attacker sends an email pretending to be from a legitimate bank, requesting the recipient to update their account information by clicking on a link and entering their credentials on a fake login page. The unsuspecting victim provides their sensitive information, which the attacker then uses for malicious purposes.

4. Drive-By Downloads

Drive-by download attacks exploit vulnerabilities in a user’s browser or plugins to download and execute malicious code onto their system without their consent or knowledge. This code can perform various malicious actions, such as stealing data or installing additional malware.

Example: A user visits a compromised website that contains hidden malicious code. This code exploits a vulnerability in the user’s browser to silently download and execute malware onto their system, infecting it without the user’s awareness.

5. Man-in-the-Middle (MitM) Attacks

MitM attacks intercept communication between a user’s browser and a website, allowing attackers to eavesdrop on or modify the data exchanged. This can lead to data theft, session hijacking, or the injection of malicious content.

Example: An attacker positioned between a user and a public Wi-Fi hotspot intercepts the user’s HTTP requests. The attacker can view and modify the data transmitted between the user’s browser and websites, potentially capturing sensitive information such as login credentials or injecting malware into web pages.

6. Clickjacking

Clickjacking involves tricking users into clicking on something different from what they perceive. Attackers typically overlay transparent elements on top of legitimate web content to deceive users into interacting with hidden elements, such as buttons or links, which perform unintended actions.

Example: An attacker creates a malicious website that overlays an invisible iframe on top of a legitimate webpage, such as a social media “like” button. When the victim visits the attacker’s site and attempts to click the visible content, they unknowingly interact with the hidden iframe, triggering actions like posting unwanted content on social media.

7. Browser Hijacking

Browser hijacking occurs when malware takes control of a user’s browser, often through malicious browser extensions, toolbars, or plugins. The hijacked browser may redirect users to malicious websites, change their homepage or search engine settings, or inject unwanted ads.

Example: A user inadvertently installs a browser extension that claims to enhance web browsing but is actually malicious. Once installed, the extension modifies the browser’s settings to redirect the user’s searches to a fake search engine that displays ads or collects browsing data for the attacker.

8. Session Hijacking

Session hijacking involves stealing a user’s session token or cookies to impersonate them and gain unauthorized access to their accounts. Attackers intercept or obtain these tokens through various means, such as network eavesdropping or exploiting vulnerabilities in web applications.

Example: An attacker on the same unsecured Wi-Fi network as the victim intercepts their unencrypted HTTP traffic. By capturing the victim’s session cookies, the attacker can then use these cookies to authenticate themselves as the victim and gain access to their accounts without needing their login credentials.

9. Tabnabbing

Tabnabbing is a type of phishing attack that targets users who have multiple browser tabs open. When a user switches to a different tab and then returns to an inactive tab, the content of the tab has been replaced with a malicious page designed to mimic a legitimate site, prompting the user to re-enter sensitive information.

Example: A user has multiple tabs open, including one logged into their online banking account. After switching to another tab and returning to the banking tab, they find that the page has been replaced with a fake login page that closely resembles the bank’s website. Believing they have been logged out, the user enters their credentials, which are then captured by the attacker.

10. Formjacking

Formjacking involves injecting malicious code into web forms on e-commerce websites to steal payment card details and other sensitive information entered by users. Attackers typically exploit vulnerabilities in the website’s code to intercept and exfiltrate the data entered by unsuspecting users.

Example: An attacker compromises the checkout page of an online store by injecting malicious JavaScript code. When a user enters their credit card information to complete a purchase, the code silently captures the data and sends it to the attacker’s server, allowing them to steal the user’s payment card details for fraudulent purposes.

How to Protect Your End-Users from Web Browser Attacks?

The lack of control over end users’ browsers might limit your ability to entirely thwart attacks. However, you can employ tactics for protecting end users from browser-based attacks.

Keep Software Updated

Browser Updates: Regularly update your web browser to the latest version, as updates often include security patches that fix known vulnerabilities.

Plugin/Extension Updates: Ensure that browser plugins/extensions, such as Adobe Flash, Java, and browser add-ons, are up-to-date. Consider uninstalling unnecessary or outdated plugins/extensions.

Use a Secure Browser

Choose browsers known for their security features, such as Google Chrome, Mozilla Firefox, Microsoft Edge, or Safari. These browsers often have built-in security mechanisms and frequent updates.

Consider using a security-focused browsers, such as Brave or Tor Browser, which prioritize user privacy and security.

Enable Automatic Updates

Enable automatic updates for your browser and plugins/extensions whenever possible. This ensures that you receive security patches as soon as they are available, reducing the window of vulnerability.

Use Security Software

Install reputable antivirus and anti-malware software on your device. These programs can detect and remove malicious software, including browser-based threats.

Consider using browser security extensions or plugins that provide additional protection against malicious websites, phishing attempts, and other online threats.

Reduce Your Attack Surface with Browser Isolation

The primary strategy that has been gaining traction over the past few years. It reduces attack surfaces and protects against web browser attacks. Browser isolation separates browser activity from endpoints and networks.

It executes all web page codes in secure virtual containers. This minimizes the attacker’s ability to move laterally and infiltrate systems.

All malware is boxed in containers. A passive visual representation of the content will be provided when a user requests it. So, if the user clicks on a malicious attachment, the malware stays in the secure container. It does not reach the system.

The browser isolation is easy to deploy and scale. Yet, the biggest downside is that the user experience may not be reliable. It may be less than ideal.

Vulnerability Assessments

Risk detection stands as another pivotal element in browser security, employing an array of tools and methodologies to unearth potential threats and vulnerabilities. This encompasses activities like malware scanning, phishing detection, and recognition of suspicious activities.

Conduct regular vulnerability assessments and penetration testing of your applications to identify and prioritize security weaknesses.

Utilize automated scanning tools to detect common vulnerabilities such as XSS, SQL injection, CSRF, and insecure configuration settings.

Perform manual pen testing to uncover more complex vulnerabilities that automated tools may miss.

Input Validation and Output Encoding

Validate and sanitize all user inputs to prevent injection attacks such as XSS and SQL injection.

Use parameterized queries and prepared statements to prevent SQL injection vulnerabilities.

Encode output data using proper encoding techniques (e.g., HTML entity encoding, JavaScript escaping) to mitigate XSS vulnerabilities.

Implement Web Security Headers

Implement these headers in your web server configuration or within your web application to enhance security and protect against common web-based attacks.

• Content Security Policy (CSP): Define trusted sources for content like scripts and stylesheets to prevent XSS attacks. Implement by setting the Content-Security-Policy header.
• HTTP Strict Transport Security (HSTS): Enforce HTTPS-only connections to prevent downgrade attacks. Set the Strict-Transport-Security header with a max-age directive.
• X-Content-Type-Options: Prevent MIME-type sniffing vulnerabilities by setting the X-Content-Type-Options header to nosniff.
• X-Frame-Options: Mitigate clickjacking by controlling framing behavior. Set the X-Frame-Options header to DENY or SAMEORIGIN.
• Referrer Policy: Control referrer information shared with external sites to protect user privacy. Set the Referrer-Policy header to specify the desired policy.
• Cross-Origin Resource Sharing (CORS): Control access to resources from different origins to prevent cross-origin attacks. Configure the Access-Control-Allow-Origin header to specify allowed origins.

Enable Click-to-Play for Plugins

Configure your browser to require permission before running plugins, such as Adobe Flash or Java. This reduces the risk of drive-by download attacks by preventing malicious content from automatically executing.

Exercise Caution When Clicking Links

Be cautious when clicking on links in emails, social media posts, or websites, especially if they seem suspicious or unsolicited. Hover over links to preview the URL before clicking to verify their legitimacy.

Avoid downloading files from untrusted sources or clicking on pop-up ads, as they may lead to drive-by downloads or other malware infections.

Use HTTPS Everywhere

Prefer websites that use HTTPS (Hypertext Transfer Protocol Secure) encryption for secure communication. HTTPS encrypts data transmitted between your browser and the website, protecting it from interception and tampering by attackers.

Educate Users

Raise awareness among users about common web browser-based attacks, such as phishing, XSS, and drive-by downloads. Provide training on how to identify suspicious websites, emails, and social engineering tactics.

Encourage users to report any suspicious activity or security incidents promptly.

Implement Network Security Measures

Use a firewall to monitor and control incoming and outgoing network traffic, blocking access to malicious websites and known attack vectors.

Segment your network to isolate sensitive systems and limit the impact of potential breaches.

Implement Client-Side Protection

Even though you cannot control how end-users use the browsers (they may use outdated browsers, insecure plug-ins, etc.), implementing client-side protection is important to protect end-users.

This is especially critical in defending against web browser-based threats like skimming attacks, malware injections, and formjacking. These attacks capitalize on application vulnerabilities, often by injecting malicious JavaScript (JS) scripts.

Stay tuned for more relevant and interesting security articles. Follow Indusface on Facebook, Twitter, and LinkedIn.