oai_redirection

Tracking area update reject is 10 (IMPLICITLY DETACHED)
Service attach reject for redirection : 2 (IMSI Unkown in HLR) or 17 (Network failure or user busy)
Service attach reject for Dos : 3,7,8,9,14 code
Service attach reject without denied of service : 15 (No suitable cells in this area)

videos tutorials and conferences

conferences
conferences2

Schematics description

• Classic flow

• IMSI-Catcher for non programmer without modification but with denied of service

• IMSI-Catcher for programmer with modification but without denied of service

• IMSI-Catcher for programmer with modification but with denied of service and redirection

oai_redirection

The changement will describe for making OAI IMSI-CATCHER or redirection
Have a look on this tutorial for installation of OAI:

• https://open-cells.com/index.php/2019/09/22/all-in-one-openairinterface/

Have a look on this tutorial for doing the OAI redirection :

• https://icepng.github.io/2020/09/23/RRCConnectionRelease/
  
  PATCH is in the file asn1_msg.c as : https://github.com/SitrakaResearchAndPOC/oai_redirection/blob/main/asn1_msg_diff.txt

REJECTION PROCESS AT OAI-CN :

• all rejection message is definead at :

gedit src/nas/api/network/as_message.h

• For changing tracking_area_update_reject : (by default EMM_CAUSE_IMPLICITLY_DETACHED coded as 10)

gedit src/nas/emm/TrackingAreaUpdate.c  

• search and change this code :

rc = emm_proc_tracking_area_update_reject (ue_id, EMM_CAUSE_IMPLICITLY_DETACHED);  

NB :

• WITH JUST COLLECTOR AND JAMMER -> Denied of service afer imsi-catcher ( ILLEGAL_UE coded 3) for default service_attach_reject

• NO NEED DENIDED OF SERVICE , MODIFY service_attach_reject as NAS_CAUSE_NO_SUITABLE_CELLS_IN_TRACKING_AREA (ONLY ACTIVE IMSI-CATCHER)

• For changing service_attach_reject :

gedit src/nas/nas_proc.c   

search DIAMETER_AUTHENTICATION_DATA_UNAVAILABLE (before s6a_error)

IF UE is not in database, it will send this error so change with code reject
all code is at : src/nas/api/network/as_message.h
For example : NAS_CAUSE_NO_SUITABLE_CELLS_IN_TRACKING_AREA (coded 15) if we want to make IMSI-CATCHER

This error code will be re-apply as attach_reject->emmcause on :

gedit src/nas/emm/msg/AttachReject.c 

Modification for redirection at openairinterface5g

find -name asn1_msg.c 

find -name ASN1_files/EUTRA-RRC-Definitions-a20.asn

find -name LTE_RedirectedCarrierInfo*

find -name LTE_RedirectedCarrierInfo.c

find -name LTE_RedirectedCarrierInfo.h

find -name LTE_CarrierFreqsGERAN*

find -name LTE_CarrierFreqsGERAN.h

For building oai for redirection, use release 14

./build_oai -I --eNB -x --install-system-files -w USRP -r Rel14

Redirection changement :

rrcConnectionRelease->criticalExtensions.choice.c1.choice.rrcConnectionRelease_r8.redirectedCarrierInfo = &rInfo;