The 4G EPC, or Evolved Packet Core, is the central control and packet-processing layer of an LTE network. It handles subscriber authentication, mobility, policy enforcement, and session setup, deciding how a device connects and keeps data flowing as it moves between cells. Unlike the radio interface, the EPC is mostly internal infrastructure, so many systems assume its messages are trustworthy.
That trust makes the EPC a high-value target. If an attacker can abuse signaling or session-state logic, they may disrupt service, force reconnects, or hijack an active session. Defenders therefore focus on mutual authentication, strict authorization, and validating protocol state at every boundary. In practice, EPC security means treating internal network traffic as potentially hostile and checking that each control message is expected, well-formed, and permitted.