PFCP Protocol
Packet Forwarding Control Protocol Security Testing
Packet Forwarding Control Protocol (PFCP) is used in 4G and 5G mobile core networks to control user-plane functions from the control plane. It manages how traffic is forwarded, filtered, and accounted for in elements such as SGW, PGW, and UPF.
CyTAL assesses PFCP implementations to identify vulnerabilities that could disrupt mobile data services or impact core network stability.
What Is PFCP?
PFCP is defined by 3GPP and provides a standardised interface between control-plane and user-plane functions. It is used to:
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Create, modify, and delete forwarding rules
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Manage session and bearer state
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Configure traffic detection and forwarding actions
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Support policy and charging enforcement
PFCP typically runs over UDP and is critical to mobile core operation.
How PFCP Communication Works
PFCP communication typically involves:
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Establishing a PFCP association between control and user-plane nodes
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Exchanging session establishment and modification messages
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Installing or updating forwarding and reporting rules
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Removing sessions and releasing resources
Correct handling of message sequences and state is essential for reliable operation.
Common PFCP Vulnerabilities
PFCP implementations may expose vulnerabilities such as:
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Malformed message parsing flaws
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State machine and session handling errors
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Resource exhaustion through signalling floods
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Improper validation of rules and parameters
These issues can lead to denial of service or disruption of user traffic.
PFCP Testing with ProtoCrawler
CyTAL uses ProtoCrawler to perform automated, protocol-aware security testing of PFCP implementations.
ProtoCrawler testing includes:
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Fuzzing PFCP headers and information elements
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Injection of invalid or unexpected state transitions
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Stress testing session and rule management
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Validation of protocol compliance and error handling
This testing uncovers control-plane to user-plane interaction weaknesses.
Why PFCP Security Matters
PFCP controls how user traffic is forwarded in mobile cores. Vulnerabilities in PFCP handling can:
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Disrupt data services at scale
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Cause widespread service instability
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Enable signalling-based denial-of-service attacks
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Impact 4G and 5G network reliability
Protocol-level testing helps ensure resilient mobile core deployments.
Frequently Asked Questions
How does ProtoCrawler test PFCP implementations?
ProtoCrawler generates valid and malformed PFCP messages to evaluate parsing, state handling, and robustness.
Can ProtoCrawler detect signalling-based denial-of-service issues?
Yes. ProtoCrawler can identify resource exhaustion and session handling weaknesses.
Is PFCP used in both 4G and 5G networks?
Yes. PFCP is used in LTE EPC and 5G Core architectures to control user-plane functions.
Can ProtoCrawler test virtualised and cloud-native core network functions?
Yes. ProtoCrawler supports testing of physical, virtual, and cloud-native PFCP implementations.
What results does ProtoCrawler provide after PFCP testing?
ProtoCrawler provides detailed traces, crash reports, and reproducible test cases.
Get Started with PFCP Security Testing
Identify mobile core control vulnerabilities before they impact user services with CyTAL’s automated protocol security testing.
Contact CyTAL to learn how ProtoCrawler can help secure your PFCP implementations.