Duplicate ICAO 24-bit aircraft addresses and SSR
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m99 thanks,
Yes, ADS-B, the younger brother of Mode-S SSR, is a security threat:
http://www.icao.int/APAC/Documents/e...urity_adsb.pdf
By the way, satellite data links may lack authentication. We are surrounded by insecure systems and a good hacker certainly a good intelligence service can exploit the vulnerabilities.
If SSRs compliant with the European Mode S Station Functional Specification may suffer from ID duplication effects this could have far reaching implications. For example it may be possible to hijack a plane while flying a decoy plane in the opposite direction. The hijacked plane may then go black and disappear while SAR is diverted to look for the decoy. This of course requires resources and capabilities not available to ordinary terrorists.
Yes, ADS-B, the younger brother of Mode-S SSR, is a security threat:
http://www.icao.int/APAC/Documents/e...urity_adsb.pdf
By the way, satellite data links may lack authentication. We are surrounded by insecure systems and a good hacker certainly a good intelligence service can exploit the vulnerabilities.
If SSRs compliant with the European Mode S Station Functional Specification may suffer from ID duplication effects this could have far reaching implications. For example it may be possible to hijack a plane while flying a decoy plane in the opposite direction. The hijacked plane may then go black and disappear while SAR is diverted to look for the decoy. This of course requires resources and capabilities not available to ordinary terrorists.
If SSRs compliant with the European Mode S Station Functional Specification may suffer from ID duplication effects this could have far reaching implications. For example it may be possible to hijack a plane while flying a decoy plane in the opposite direction. The hijacked plane may then go black and disappear while SAR is diverted to look for the decoy. This of course requires resources and capabilities not available to ordinary terrorists.
It is not possible to hide from an SSR or a multilateration system in that way. As soon as the transponder drops out of lockout (typically 18s) it will immediately become visible to radar again - even if it does have a duplicate address. Multilateration systems do not even have to wait that long as the transponder squitter is ever present and and position is enough of a discriminator to overcome any duplicate address. Radar could cope with dozens of aircraft squawking Mode A 7000 with the old technology. Mode S is nothing if not at least as good at detecting duplicates.
The only way to make the target go black is to switch the transponder off. Which we knew already!
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Dont Hang Up,
I hesitated for a long time whether to post the provocative paragraph you are citing. It sounds not only fanciful but crazy.
However please note that the EASA document cited in the first post of this thread describes the ID duplication effects in this way:
* One (or more) of the aircraft involved may be assessed by the Mode S interrogator to be a false or reflected echo, and subsequently ignored. These aircraft will not then be displayed to air traffic controllers.
* In the case of aircraft whose flight paths cross, the identification labels of those aircraft may inadvertently ‘swap’ (i.e. replace one another) on air traffic controllers displays, thereby presenting controllers with incorrect information and creating the possibility of misidentification.
If these two effects can combine in a certain way it may be possible to cheat the SSR.
I don't claim anything regarding multilateration systems.
Please note that the EASA document being published about 6 years after the European Mode S Station Functional Specification seems to suggest that even compliant radars may suffer from ID duplication effects.
I hesitated for a long time whether to post the provocative paragraph you are citing. It sounds not only fanciful but crazy.
However please note that the EASA document cited in the first post of this thread describes the ID duplication effects in this way:
* One (or more) of the aircraft involved may be assessed by the Mode S interrogator to be a false or reflected echo, and subsequently ignored. These aircraft will not then be displayed to air traffic controllers.
* In the case of aircraft whose flight paths cross, the identification labels of those aircraft may inadvertently ‘swap’ (i.e. replace one another) on air traffic controllers displays, thereby presenting controllers with incorrect information and creating the possibility of misidentification.
If these two effects can combine in a certain way it may be possible to cheat the SSR.
I don't claim anything regarding multilateration systems.
Please note that the EASA document being published about 6 years after the European Mode S Station Functional Specification seems to suggest that even compliant radars may suffer from ID duplication effects.
Whilst I would not wish to disparage EASA, I would question their need to raise theoretical and largely unwarranted concerns about Mode S address duplication.
As I have stated previously on this thread, a Mode S radar has no issue with handling targets with duplicate address. The principle of using address as a means of identifying reflections has some merit but the idea that a radar designer would use address as the sole discriminator and deliberately reject duplicates is not plausible as real duplicates have been a known (though increasingly rare) occurrence since Mode S became operational many years ago.
Code swapping was a well know phenomenon to ATCOs with the old Mode A/C technology when any two targets came into close lateral proximity - even if well separated in height. A transitory inconvenience except possibly in a holding stack (hence radar control was not permitted there). For Mode S the issue would be similar but ONLY in the case of the two targets having a duplicate address.
TCAS is the only technology that really struggles with Mode S duplicates. However TCAS is a safety net and operates on the basis that when it works it helps and when it does not then you are no worse of than without it.
* One (or more) of the aircraft involved may be assessed by the Mode S interrogator to be a false or reflected echo, and subsequently ignored. These aircraft will not then be displayed to air traffic controllers.
* In the case of aircraft whose flight paths cross, the identification labels of those aircraft may inadvertently ‘swap’ (i.e. replace one another) on air traffic controllers displays, thereby presenting controllers with incorrect information and creating the possibility of misidentification.
TCAS is the only technology that really struggles with Mode S duplicates. However TCAS is a safety net and operates on the basis that when it works it helps and when it does not then you are no worse of than without it.
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Dont Hang Up thanks.
I understand that you accept the possibility of track swapping but not that of track dropping. Being new to radar technology I'm still struggling with the technical literature and can't offer a useful opinion.
There are some indications that the provocative scenario did happen but the SSR in question had severe maintenance issues, may have been non-compliant with the European specification and there is a possibility of jamming.
I understand that you accept the possibility of track swapping but not that of track dropping. Being new to radar technology I'm still struggling with the technical literature and can't offer a useful opinion.
There are some indications that the provocative scenario did happen but the SSR in question had severe maintenance issues, may have been non-compliant with the European specification and there is a possibility of jamming.
