Summary
MediaFlow Proxy contains a server-side request forgery vulnerability in its /proxy routes because the d query parameter is not consistently validated. A remote attacker may cause the proxy to request attacker-selected internal destinations, including loopback services and cloud metadata endpoints, and return the responses.
Affected context
The issue occurs in MediaFlow Proxy deployments that expose the /proxy routes and use the d query parameter to determine the upstream destination. Risk increases when the proxy can reach internal administrative services, loopback interfaces, private network addresses, or cloud instance metadata services and returns upstream responses to the requester.
Exploit preconditions
- Attack surface: Publicly or remotely reachable
/proxyroutes - Required access: Ability to submit requests to the proxy; authentication requirements depend on deployment configuration
- Trigger point: Processing of a request containing a destination in the
dquery parameter - Why exploitation is possible: Destination validation is missing or incomplete, allowing requests to attacker-selected internal or otherwise restricted URLs
Why this happens
The vulnerability results from treating a user-controlled proxy destination as trustworthy without applying comprehensive validation before making the outbound request. Incomplete controls may permit loopback, private-network, link-local, or cloud metadata destinations, which maps to CWE-918: Server-Side Request Forgery. The insecure pattern is an unrestricted server-side fetch whose destination and response handling are controlled by external input.
Potential impact
- An attacker may read responses from internal services
- Sensitive cloud metadata or temporary credentials could be exposed
- Internal administrative interfaces could be reached through the proxy
- Network segmentation controls could be bypassed
- The proxy could be used to scan or interact with private network resources
General mitigation guidance
Mitigation typically focuses on making outbound request destinations deny-by-default and reducing trust in client-supplied URLs.
Common defensive patterns include:
- Allowing only explicitly approved schemes, hosts, ports, and destination networks
- Rejecting loopback, private, link-local, multicast, and cloud metadata address ranges
- Resolving hostnames and validating the resulting addresses before connecting
- Revalidating destinations after redirects and preventing unrestricted redirect following
- Returning only the minimum response data required by the application
- Restricting proxy network egress with firewall or service-mesh policy
- Running the proxy with least-privilege network and cloud permissions
How teams detect issues like this
Organizations commonly detect SSRF risks through:
- Static analysis rules for server-side HTTP clients receiving URL or host values from request parameters
- Code review checks for missing scheme, hostname, port, redirect, and IP-range validation
- Dynamic testing with loopback, private-range, link-local, and metadata-service destinations in controlled environments
- Network monitoring for unexpected outbound connections from the proxy process
- Egress policies that alert on access to internal services or cloud metadata endpoints
Automated security review tools can help identify user-controlled URL flows, but findings should be verified against deployment-specific network behavior.
