Remote Code Execution Vulnerability via SSTI in Fides Webserver Jinja Email Templating Engine
Date: 2024-09
Affected: pip/ethyca-fides
Attack vector: rce
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2024-45053
CWE: CWE-1336
CWE-94
CVSS: 9.1 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H)

### Summary The Email Templating feature uses Jinja2 without proper input sanitization or rendering environment restrictions, allowing for Server-Side Template Injection that grants Remote Code Execution to privileged users. A privileged user refers to an Admin UI user with the default `Owner` or `Contributor` role, who can escalate their access and execute code on the underlying Fides Webserver container where the Jinja template rendering function is executed. ### Details The application enables the creation of message templates that are sent via email to Fides Privacy Center users (data subjects) who raise privacy requests such as data subject access requests or consent management requests via the Privacy Center. These emails are triggered at various points in the request processing flow, for example when a request is denied or approved. The messages are defined using Jinja2 templates, allowing the use of statement and expression directives to craft more complex messages that include dynamic variables. It was discovered that the Jinja2 environment used to render the templates does not restrict the usage of common Python methods and objects, which permits an attacker to execute arbitrary code via Server-Side Template Injection. An attacker with the ability to modify email templates can inject malicious code, which is then executed when an email message is rendered and sent to the user. Admin UI users assigned the following default roles are permitted to modify email templ


Mitigations:

Architectural layers (MAESTRO):