| 제목 | Open5GS 2.7.6 Incorrect Authorization |
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| 설명 | The AMF in Open5GS v2.7.6 (and main branch) resolves UE-associated NGAP messages by AMF-UE-NGAP-ID via a process-wide pool lookup (ran_ue_find_by_amf_ue_ngap_id in src/amf/context.c) without verifying that the message arrived on the SCTP/TNLA association bound to the resolved UE's serving gNB.
A second NG-RAN node that has completed its own NG Setup with the AMF can submit a single forged PDUSessionResourceSetupResponse carrying a victim UE's AMF-UE-NGAP-ID and an attacker-controlled GTP-U endpoint. The AMF accepts the message and forwards the supplied transfer to the SMF as Nsmf_PDUSession_UpdateSMContext, causing the SMF to reprogram the UPF's Forwarding Action Rule and deliver the victim UE's downlink user-plane traffic to the attacker's gNB.
This violates the per-NG-RAN-node scope of UE-associated NGAP signalling defined in 3GPP TS 38.413 §10.6 and §9.3.3.2. |
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| 원천 | ⚠️ https://github.com/open5gs/open5gs/issues/4498 |
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| 사용자 | Seungjoon Na (UID 97657) |
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| 제출 | 2026. 04. 28. AM 04:17 (6 개월 ago) |
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| 모더레이션 | 2026. 05. 16. PM 02:38 (18 days later) |
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| 상태 | 수락 |
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| VulDB 항목 | 364330 [Open5GS 까지 2.7.6 AMF/MME src/amf/context.c ran_ue_find_by_amf_ue_ngap_id 권한 상승] |
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| 포인트들 | 20 |
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