Summary
A server-side request forgery vulnerability in Dify allows an unauthenticated remote attacker to supply a URL that the server retrieves. Depending on network placement and access controls, this may expose internal services or cloud metadata and allow the server to be used as a network pivot.
A server-side request forgery vulnerability in Dify allows an unauthenticated remote attacker to supply a URL that the server retrieves. Depending on network placement and access controls, this may expose internal services or cloud metadata and allow the server to be used as a network pivot.
Affected context
The issue occurs in Dify deployments where the remote file upload endpoint accepts attacker-controlled URLs without authentication or adequate destination validation. Risk is greater when the Dify server can reach private network services, instance metadata endpoints, or other privileged infrastructure.
The issue occurs in Dify deployments where the remote file upload endpoint accepts attacker-controlled URLs without authentication or adequate destination validation. Risk is greater when the Dify server can reach private network services, instance metadata endpoints, or other privileged infrastructure.
Exploit preconditions
- Attack surface: The remote file upload HTTP endpoint
- Required access: Network access to the endpoint; authentication is not required
- Trigger point: Server-side retrieval of a URL supplied in the request
- Why exploitation is possible: The server initiates outbound requests without sufficiently restricting destinations or validating whether they belong to trusted external resources
- Attack surface: The remote file upload HTTP endpoint
- Required access: Network access to the endpoint; authentication is not required
- Trigger point: Server-side retrieval of a URL supplied in the request
- Why exploitation is possible: The server initiates outbound requests without sufficiently restricting destinations or validating whether they belong to trusted external resources
Why this happens
The underlying bug is an unrestricted server-side URL fetch. User-controlled input is treated as a trusted resource location, causing the application to make network requests from its own privileged network position. This maps to CWE-918, Server-Side Request Forgery, because attacker-selected destinations can include internal services or metadata interfaces that are not directly reachable by the attacker.
The underlying bug is an unrestricted server-side URL fetch. User-controlled input is treated as a trusted resource location, causing the application to make network requests from its own privileged network position. This maps to CWE-918, Server-Side Request Forgery, because attacker-selected destinations can include internal services or metadata interfaces that are not directly reachable by the attacker.
Potential impact
- An attacker may retrieve sensitive information from internal services
- Cloud instance or workload metadata could be exposed
- The Dify server could be used as a network pivot
- Internal administrative interfaces may be probed or accessed
- Confidentiality of application or infrastructure data could be reduced
- An attacker may retrieve sensitive information from internal services
- Cloud instance or workload metadata could be exposed
- The Dify server could be used as a network pivot
- Internal administrative interfaces may be probed or accessed
- Confidentiality of application or infrastructure data could be reduced
General mitigation guidance
Mitigation generally focuses on eliminating arbitrary server-side URL
retrieval and reducing the trust placed in user-provided resource locations.
Common defensive patterns include:
- Allowing outbound requests only to approved schemes, hosts, and ports
- Applying strict allowlists for remote file sources where business needs require them
- Resolving hostnames and validating resulting addresses against private, loopback, link-local, and metadata ranges
- Rechecking destinations after redirects and limiting redirect behavior
- Enforcing outbound network policies and egress proxies at the deployment layer
- Avoiding access to cloud metadata services from application workloads
- Applying least-privilege network and service-account permissions
- Requiring authentication and authorization for file-fetching functionality where appropriate
Mitigation generally focuses on eliminating arbitrary server-side URL
retrieval and reducing the trust placed in user-provided resource locations.
Common defensive patterns include:
- Allowing outbound requests only to approved schemes, hosts, and ports
- Applying strict allowlists for remote file sources where business needs require them
- Resolving hostnames and validating resulting addresses against private, loopback, link-local, and metadata ranges
- Rechecking destinations after redirects and limiting redirect behavior
- Enforcing outbound network policies and egress proxies at the deployment layer
- Avoiding access to cloud metadata services from application workloads
- Applying least-privilege network and service-account permissions
- Requiring authentication and authorization for file-fetching functionality where appropriate
How teams detect issues like this
Detection approaches can include:
- Static analysis for HTTP clients invoked with user-controlled URLs
- Code review checks for missing destination validation, redirect controls, and
authentication around fetch endpoints
- Dynamic testing with controlled internal test services and blocked destination
classes
- Network monitoring for application requests to private address ranges,
metadata endpoints, unusual ports, or unexpected external domains
- Egress policy enforcement and alerts for denied or anomalous outbound requests
- Automated security review tools that identify SSRF-prone data flows
Detection approaches can include:
- Static analysis for HTTP clients invoked with user-controlled URLs
- Code review checks for missing destination validation, redirect controls, and
authentication around fetch endpoints
- Dynamic testing with controlled internal test services and blocked destination
classes
- Network monitoring for application requests to private address ranges,
metadata endpoints, unusual ports, or unexpected external domains
- Egress policy enforcement and alerts for denied or anomalous outbound requests
- Automated security review tools that identify SSRF-prone data flows
