Open Redirects

What Are Open Redirects

Open redirects allow users to be redirected from one page to another without validation. They're a security risk because attackers can manipulate the redirect to send users to malicious sites.

How Error Messages Lead to Information Exposure:

Error messages are an inevitable part of any software. While they aim to provide users with feedback to resolve issues, they often expose sensitive data. This unintended information exposure compromises user Privacy and Security.

Also known as URL Redirection Vulnerability, Unvalidated Redirects and Forwards, Open URL Redirect, Unsafe URL Redirection and Untrusted URL Forwarding

As a website owner, you must find and fix any open redirects. Here's how:

  • Review your site for any redirects using a tool like Burp Suite or Zed Attack Proxy. Look for redirects that accept user input.
  •  For any redirects that accept input, add validation to ensure the input only contains trusted URLs. For example, only allow redirects to URLs on your domain or a list of approved external domains.
  • Monitor your site regularly and test any new features for open redirects before launching them. Attackers are always looking for new vulnerabilities, so constant vigilance is key.

By identifying and eliminating open redirects, you'll reduce the risk of your users being sent to malicious sites. Their security and your reputation depend on it. Staying on top of this issue is well worth the effort.

Understanding Open Redirects

Open redirects allow hackers to manipulate URLs to redirect users to malicious sites. They work by exploiting vulnerabilities in web apps that don't properly validate redirect destinations.

Once a hacker finds an open redirect, they can craft a URL that redirects victims to phishing pages, malware downloads, or other scam sites. For example, a hacker could redirect users of to instead of the intended destination.

To avoid open redirects, always validate redirect destinations and user input. Double-check that the destination URL begins with an approved domain before redirecting. Never blindly trust URL parameters. Keep your web frameworks and plugins current since outdated software is an easy target.

Staying vigilant and keeping your web apps secure is the best way to prevent open redirects. Be careful out there!

Potential Risks and Consequences

Open redirects also enable brand reputation damage. Hackers can redirect your site visitors to competitors’ pages or offensive content, associating your brand with negative experiences. Legal and compliance issues may arise if PII or financial data is compromised due to open redirects on your site. Regulations like GDPR require reasonable security controls so that unmitigated open redirects could lead to penalties.

Mitigation and Best Practices

To avoid open redirect vulnerabilities, follow these best practices:

Validate and sanitize all input URLs to ensure they only redirect to authorized domains. Only allow redirects to sites you trust that are relevant to your business. For example, don’t allow redirects to sites that could trick users or steal credentials.

Properly whitelist authorized redirect URLs. Only redirect to URLs that match a strict whitelist. This prevents attackers from redirecting users to malicious sites. Double-check that the whitelisted URLs are correct and legitimate.

Use safe redirect handling techniques. When generating a redirect URL, don't simply take input and paste it into the redirect. Use relative paths, and don't include user input in the hostname or protocol. For example, don't do:

redirect_to = input + “”

Also, be careful when using URL parameters in redirects, as these can be manipulated. It's best to avoid using URL parameters for redirects when possible.

By validating input, whitelisting properly, and using safe redirect handling techniques, you can mitigate the dangers of open redirects and keep your users safe. constant vigilance and proactively hunting for these kinds of issues is key.

Tools and Techniques for Detection

There are a few techniques security professionals use to detect open redirects.

Manual Code Review

Manually reviewing application code is an effective way to identify open redirect vulnerabilities. Security engineers analyze the logic in URL redirection functionality to ensure external URLs are properly validated and sanitized before redirecting users. They also test redirect parameters to confirm external URLs cannot be manipulated.

Though manual code reviews are time-consuming, they provide high accuracy in finding critical open redirect flaws. Automated scanners often miss these subtle vulnerabilities that human experts can spot. Experienced application security professionals should perform manual code reviews.

Frequently Asked Questions (FAQs)

What are open redirects, and why are they concerned for mobile app developers and owners?

Open redirects allow users to be redirected from one page to another without validation, posing a security risk. For mobile app developers and owners, this vulnerability can be exploited by attackers to redirect users to malicious sites or phishing pages, compromising the app's reputation and user data.

How can mobile app developers identify open redirects in their applications?

Mobile app developers can use tools like Appknox to scan their apps for open redirect vulnerabilities. Automated scanners help identify potential flaws and security risks in the app's redirect functionality, ensuring timely detection and mitigation.

What measures can mobile app owners take to prevent open redirect vulnerabilities?

Mobile app owners should prioritize security during the development process and follow best practices. Validating and sanitizing all input URLs, whitelisting authorized redirect URLs, and using safe redirect handling techniques are crucial steps to prevent open redirect vulnerabilities.

Can open redirects in mobile apps lead to compliance issues or legal consequences?

Yes, open redirects that compromise users' personal or financial data can lead to compliance violations and legal consequences. Regulations like GDPR require app owners to implement reasonable security controls, making it essential to address open redirect vulnerabilities.

How can Appknox help secure mobile apps against open redirects and cyber threats?

Appknox offers comprehensive security solutions for mobile app developers and owners, including scanning for open redirect vulnerabilities. Their tools and expertise can help identify and fix potential security issues, ensuring your app remains protected from cyber threats.


In conclusion, open redirects pose a hidden threat, but with vigilance, you can avoid falling victim to them. Stay wary of unverified links, and never click unsolicited URLs in emails or messages. Use a tool like the Redirect Detective to analyze any link before clicking to ensure it goes where it claims. Enable two-factor authentication on accounts whenever possible, adding an extra layer of protection. And if anything ever feels off about a website or link, trust your instincts—it's better to be safe than sorry. Staying cautious and keeping your guard up is the best way to steer clear of open redirect attacks

Take the first step towards safeguarding your digital presence with Appknox. Our comprehensive security solutions can help protect your business from open redirect vulnerabilities and other cyber threats. Schedule a free demo today!