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2020-001: URL Redirection to Untrusted Site ('Open Redirect') in Google generic TLD and ccTLD

2020-001: URL Redirection to Untrusted Site ('Open Redirect') in Google generic TLD and ccTLD

Original release date: March 1, 2020
Last revised:
Discovered by: Vicente Aguilera Díaz
Severity: 4.7/10 (CVSSv3 Base Score)
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N


The generic TLD ( and country code top-level domain (ccTLD) are affected by this vulnerability.


An open redirect is a vulnerability that occurs when an application that takes a parameter and redirects a user to the parameter value without any validation.

This vulnerability is used for phishing attacks for redirecting users to visit malicious sites against their will.

Although Google shows an alert message to notify users if a redirection is generated, it is possible to create a malicious URL that avoids these alert messages.

Google is affected by this vulnerability in the images search functionality.



When a user search an image, generates a link as the following:

The "url" parameter is not properly validated, so an open redirect can be exploited through this parameter.

Only this parameter is mandatory, so we can exclude some parameters in the GET request because not affect the expected results:

How to reproduce the vulnerability:

1. Select the malicious URL
For example:

2. Create the URL redirection to avoid the Google alert message

For example:

3. Encode the URL redirection

For that, we can use some service as "".

For example:

4. Create the final URL without Google alert


The user may be redirected to an untrusted page that contains malware which may then compromise the user's machine. This will expose the user to extensive risk and the user's interaction with the web server may also be compromised if the malware conducts keylogging or other attacks that steal credentials, personally identifiable information (PII), or other important data.

The user may be subjected to phishing attacks by being redirected to an untrusted page. The phishing attack may point to an attacker controlled web page that appears to be a trusted web site. The phishers could then steal the user's credentials and then use these credentials to access the legitimate web site.


The generic TLD ( and country code top-level domain (ccTLD) are affected by this vulnerability.




March 1, 2020: Initial release


  • March 1, 2020: Vulnerability acquired by Internet Security Auditors (
  • March 1, 2020: Vulnerability report send to Google.



The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Internet Security Auditors accepts no responsibility for any damage caused by the use or misuse of this information.


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