Summary
Froxlor contains a stored cross-site scripting vulnerability in its SSL certificate handling. A low-privileged customer may be able to place script content in a certificate issuer field, which can execute when an administrator or reseller views the certificate list.
Affected context
The issue occurs in Froxlor deployments where customers can upload SSL certificates for domains they control and the resulting issuer organization value is displayed in the administrative certificate listing. Risk is present when that value is stored without output-safe encoding and rendered with a mechanism that disables normal HTML escaping. The affected privilege boundary is between a customer and higher-privileged administrator or reseller users.
Exploit preconditions
- Attack surface: SSL certificate upload and update functionality
- Required access: Authenticated customer-level access to a permitted domain
- Trigger point: An administrator or reseller views the SSL certificate table
- Why exploitation is possible: Attacker-influenced certificate metadata is persisted and later emitted without contextual HTML encoding
- Privilege boundary: Content supplied by a customer is processed in a session belonging to a more privileged user
Why this happens
The vulnerability results from combining insufficient output encoding with a renderer configuration that marks scalar table values as trusted HTML. Certificate metadata derived from the issuer organization field is stored verbatim, and the Twig raw filter prevents automatic escaping when the value is displayed. This maps to CWE-79: Improper Neutralization of Input During Web Page Generation, because attacker-controlled data reaches a browser as executable markup rather than contextually encoded text.
Potential impact
- A malicious customer may execute script in an administrator's browser session
- An attacker could perform privileged actions through the compromised session
- Administrator credentials or session data may be exposed
- Froxlor configuration and managed services could be altered
- Server-side command execution could occur if administrative control reaches root-operated management workflows
General mitigation guidance
Mitigation generally focuses on treating all certificate metadata and other externally derived values as untrusted data.
Common defensive patterns include:
- Applying context-appropriate HTML escaping at every output boundary
- Avoiding
rawor equivalent trust-bypassing rendering filters for user-influenced values - Validating certificate fields against a narrowly defined expected format before storage
- Separating data rendering from trusted HTML generation
- Restricting administrative privileges and minimizing the capabilities of root-operated automation
- Using browser security controls such as an effective Content Security Policy as defense in depth
- Reviewing stored data already collected from customer-controlled certificate uploads
How teams detect issues like this
Organizations can identify similar issues through:
- Static analysis rules for unescaped template variables and use of
raw-style rendering filters - Code review checks tracing uploaded files and parsed certificate metadata into administrative views
- Dynamic testing that places harmless marker values in certificate metadata and verifies contextual encoding
- Policy enforcement requiring output encoding for all customer-controlled values
- Monitoring administrative pages for unexpected script-like markup and unusual privileged actions
- Automated security review tools that flag tainted data flows into HTML responses
