Headline
GHSA-2h87-4q2w-v4hf: Strapi plugins vulnerable to Server-Side Template Injection and Remote Code Execution in the Users-Permissions Plugin
Summary
Strapi through 4.5.5 allows authenticated Server-Side Template Injection (SSTI) that can be exploited to execute arbitrary code on the server.
Details
Strapi through 4.5.5 allows authenticated Server-Side Template Injection (SSTI) that can be exploited to execute arbitrary code on the server. A remote attacker with access to the Strapi admin panel can inject a crafted payload that executes code on the server into an email template that bypasses the validation checks that should prevent code execution.
IoC
Using just the request log files, the only IoC to search for is a PUT request to URL path /users-permissions/email-templates. This IoC only indicates that a Strapi email template was modified on your server and by itself does not indicate if your Strapi server has been compromised. If this IoC is detected, you will need to manually review your email templates on your Strapi server and backups of your database to see if any of the templates contain a lodash template delimiter (eg. <%STUFF HERE%>) that contains suspicious JavaScript code. Generally speaking these templates should look like the following, you may have minor adjustments but any unrecognized code should be considered suspicious.
Reset Password Template:
<p>We heard that you lost your password. Sorry about that!</p>
<p>But don’t worry! You can use the following link to reset your password:</p>
<p><%= URL %>?code=<%= TOKEN %></p>
<p>Thanks.</p>
Email Confirmation Template:
<p>Thank you for registering!</p>
<p>You have to confirm your email address. Please click on the link below.</p>
<p><%= URL %>?confirmation=<%= CODE %></p>
<p>Thanks.</p>
Specifically you should look for odd code contained within the <%STUFF HERE%> blocks as this is what is used to bypass the lodash templating system. If you find any code that is not a variable name, or a variable name that is not defined in the template you are most likely impacted and should take immediate steps to confirm there are no malicious applications running on your servers.
Impact
All users on Strapi below 4.5.6 with access to the admin panel and the ability to modify the email templates
- GitHub Advisory Database
- GitHub Reviewed
- CVE-2023-22621
Strapi plugins vulnerable to Server-Side Template Injection and Remote Code Execution in the Users-Permissions Plugin
Critical severity GitHub Reviewed Published Apr 18, 2023 in strapi/strapi • Updated Apr 19, 2023
Package
npm @strapi/plugin-email (npm)
Affected versions
< 4.5.6
npm @strapi/plugin-users-permissions (npm)
Summary
Strapi through 4.5.5 allows authenticated Server-Side Template Injection (SSTI) that can be exploited to execute arbitrary code on the server.
Details
Strapi through 4.5.5 allows authenticated Server-Side Template Injection (SSTI) that can be exploited to execute arbitrary code on the server. A remote attacker with access to the Strapi admin panel can inject a crafted payload that executes code on the server into an email template that bypasses the validation checks that should prevent code execution.
IoC
Using just the request log files, the only IoC to search for is a PUT request to URL path /users-permissions/email-templates. This IoC only indicates that a Strapi email template was modified on your server and by itself does not indicate if your Strapi server has been compromised. If this IoC is detected, you will need to manually review your email templates on your Strapi server and backups of your database to see if any of the templates contain a lodash template delimiter (eg. <%STUFF HERE%>) that contains suspicious JavaScript code. Generally speaking these templates should look like the following, you may have minor adjustments but any unrecognized code should be considered suspicious.
Reset Password Template:
<p>We heard that you lost your password. Sorry about that!</p>
<p>But don’t worry! You can use the following link to reset your password:</p> <p><%= URL %>?code=<%= TOKEN %></p>
<p>Thanks.</p>
Email Confirmation Template:
<p>Thank you for registering!</p>
<p>You have to confirm your email address. Please click on the link below.</p>
<p><%= URL %>?confirmation=<%= CODE %></p>
<p>Thanks.</p>
Specifically you should look for odd code contained within the <%STUFF HERE%> blocks as this is what is used to bypass the lodash templating system. If you find any code that is not a variable name, or a variable name that is not defined in the template you are most likely impacted and should take immediate steps to confirm there are no malicious applications running on your servers.
Impact
All users on Strapi below 4.5.6 with access to the admin panel and the ability to modify the email templates
References
- GHSA-2h87-4q2w-v4hf
- https://nvd.nist.gov/vuln/detail/CVE-2023-22621
- strapi/strapi#15385
- strapi/strapi@921d309
- https://github.com/strapi/strapi/releases
- https://github.com/strapi/strapi/releases/tag/v4.5.6
- https://strapi.io/blog/security-disclosure-of-vulnerabilities-cve
- https://www.ghostccamm.com/blog/multi_strapi_vulns/
Published to the GitHub Advisory Database
Apr 19, 2023
Last updated
Apr 19, 2023
Related news
Strapi through 4.5.5 allows attackers (with access to the admin panel) to discover sensitive user details by exploiting the query filter. The attacker can filter users by columns that contain sensitive information and infer a value from API responses. If the attacker has super admin access, then this can be exploited to discover the password hash and password reset token of all users. If the attacker has admin panel access to an account with permission to access the username and email of API users with a lower privileged role (e.g., Editor or Author), then this can be exploited to discover sensitive information for all API users but not other admin accounts.