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Bug #2958

OsmoSGSN doesn't authenticate on second/further ATTACH REQUEST

Added by laforge 7 months ago. Updated about 1 month ago.

Status:
Stalled
Priority:
High
Assignee:
Category:
-
Target version:
-
Start date:
02/17/2018
Due date:
% Done:

50%

Estimated time:
Spec Reference:
Tags:

Description

When a new/unknown MS performs an ATTACH REQUEST for the first time, it is authenticated.

However, if that same MS later performs a second ATTACH REQUEST, even with new P-TMSI/TLLI, it is not authenticated and we simply send an ATTACH ACCEPT. This is a security problem, as it means anyone can impersonate other known-existing IMSIs.


Related issues

Related to OsmoSGSN - Bug #3302: implement a FSM for GMM Attach RequestClosed2018-05-29

History

#1 Updated by laforge 5 months ago

  • Assignee changed from sysmocom to lynxis

#2 Updated by lynxis 5 months ago

  • Status changed from New to In Progress

#3 Updated by lynxis 4 months ago

  • Status changed from In Progress to Stalled
  • % Done changed from 0 to 50

I've started to refactor the whole GMM Attach Request handling into one fsm.
This issue is already fixed in the new fsm implementation.
I've created the ttcn3 testcase

SGSN_Tests.TC_attach_second_attempt
for this.

#4 Updated by lynxis 4 months ago

  • Related to Bug #3302: implement a FSM for GMM Attach Request added

#5 Updated by laforge 4 months ago

  • Tags set to TTCN3

#6 Updated by lynxis 3 months ago

#7 Updated by lynxis about 1 month ago

The test is failing again, even under the new FSM.
The HLR integration into the test must be rewritten.

At the moment, the TTCN test case SGSN_Tests.TC_attach_second_attempt still fails, but this is fails, because the
second attach does not proceed, because TTCN explicit expect to see an Insert Subscriber Data Request.
This request will be never sent from the SGSN, because it has still valid key data.

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