Friday, May 15, 2009
Undercover Officer Down, how might SIM Access Control Class help? Part 1
Thursday, May 14, 2009
Mobile Telephone Examination Procedure
This discussion continues on the theme to highlight, over the last five years, the diminishing quality of the knowledge in mobile telephone evidence training and very poor understanding by those giving advice about or presenting mobile telephone forensic evidence and opinion.
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By way of further illustration about poor understanding which was given in an advice note regarding mobile telephone examination procedure, the advice given:
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(1) by removing the battery of certain make/model of mobile telephone can lose the date and time stamp and call history, but using a Shielding Room can prevent this because you won’t need to remove the battery.
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(1a) the party giving the advice above then went on to suggest they did not think, by and large, the above is a better methodology that should be adopted and went on to advocate that the method of producing a clone test SIM (Access Card) appeared to them to be more appropriate.
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A shielding room is used to prevent radio signals entering a given space that the shielding is designed to protect, and also prevent the mobile telephone from registering to the mobile telephone network; [it] cannot though prevent loss of full call history and date and time stamp irrespective of whether the mobile telephone is in a shielded room or not. Removing the battery on some older models of mobile telephone can lose the full call history and date and time stamp. To produce a clone test SIM (Access Card) the examiner is required at first instance to remove the battery to get to the SIM/USIM. So how is their recommendation shown (in 1a) that it is any better than the unsuitable Shielding Room scenario (in 1)?
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- For the record the point I am making is not to advocate shielding rooms or faraday bags, I am just pointing out the absurdity of the advice -
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By noting in their advice that using a Shielding Room may not be the best method (thus tacitly negativing its use) the advice then goes on to positively suggest that the examiner wouldn’t need to remove the battery because it is in a shielding room and that call history and date and time stamp on the mobile telephone would be secure. They then go on to advocate the removal of the battery which implicitly requires taking the SIM out also from the handset for the purposes of producing a clone test SIM (Access Card). Their advice is confusing as they have already admitted removing the battery can lose data.
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An examiner will naturally have to remove the SIM/USIM out of the handset anyway (thus removing the battery first is one point; another point being removing the SIM/USIM can inevitably cause loss of data in the handset - it can't be helped) because the proper order of examination requires a full examination of the SIM/USIM to get at evidence that is not readily available and obtainable by leaving the SIM/USIM in the handset during examination.
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I concluded from reading their advice that it contained so many mixed messages and conflicting use of methodologies which each method that would usually be used for the treatment of different issues in isolation were now being squeezed together to make them work, would leave an examiner following their advice open to and vulnerable to potentially discrediting their own evidence.
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Moreover, if the advice note was intended to succeed in getting an examiner to use Access Cards over Shielding Rooms then in my view it failed to convince me to use one or not the other.
Monday, February 02, 2009
SIM PIN Challenge 2
A reminder that this challenge ends on the 15th February 2009:
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http://trewmte.blogspot.com/2009/01/sim-pin-challenge.html
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No pressure here guys, but we have had the first written response to the SIM PIN Challenge from a Challenge Entrant who has just started in mobile telephone forensics. This Challenge should therefore be a walk in the park for all you mobile phone and computer forensic examiners who have given evidence about SIM Cards in Court.
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As a brief history about SIM Cards, the requirement for *Personal Identity Number (PIN) to be available in a SIM Card is defined by way of the GSM Standard GSM11.11. Moreover, GSM11.11 v3 1995 standard and onwards can be downloaded free of charge. So at least we know there is over 13 years of technical knowledge about SIM Card PIN that is traceable. Furthermore, there are other standards that are used to test for allocation and activation of PIN and the mandated execution of the function between the mobile phone and SIM Card.
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*Do remember that PIN is only used because it is comon language now, but has been made obsolete from the standards and replaced by CHV (Card Holder Verification).
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Finally, many ten of thousands of SIM Cards have been examined and their evidence, along with examiners' testimonies/experts' opinions, have been presented in criminal proceedings at Court for well over a decade. A large number of the SIM Cards presented for examination had PIN enabled, thus understanding the fundamental operation of PIN is vital to forensic investigation understanding and the evidence presented about it.
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I have sent copies of this Challenge and MOBILE FORENSICS AND EVIDENCE DEGREES/CHALLENGE (see weblink at the end of this discussion) to the following who have the responsibility for: innovation, universities and skills; and regulation of forensic sciences:
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MOBILE FORENSICS AND EVIDENCE DEGREES/CHALLENGE
Thursday, January 08, 2009
SIM PIN Challenge
So does that mean a particular EF under the MF in SIM with a logical address 3F00 0000 is always going to be the CHV1 file and would the raw data from that EF reveal a user's PIN number?
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Below are raw data extracts from three phases of SIM cards - Phase 1, Phase 2 and Phase 3 (2+) and harvested from the Master File (MF) 3F00 and an unnamed EF immediately under the MF with an address 3F00 0000.
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Your challenge, if you are interested, is to examine the raw data and corroborate whether the data reveals a user's CHV1 (PIN number) or not.
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To help, you may want to check the GSM SIM card standard GSM 11.11 to comprehend file structure, formatting and coding etc for elementary files and to learn what the standard has to say about CHV/PIN.
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As forensic investigators you shouldn't need the 'carrot and stick' approach to get you to undertake this challenge because I know how much you all love your work and can't get enough of it and that should be reward enough :-). However, the first person who posts the correct answer at Forensic Focus , I am sure we can sort out some sort of prize:
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http://www.forensicfocus.com/index.php?name=Forums&file=viewtopic&t=3349
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However, there are some rules (there is always something like this):
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1) In your answer it should contain identification to a document or weblink that supports the answer (the document/weblink must be traceable and not based on "something somebody told you"). This will be checked before any prize is awarded.
2) Challenge closes 15th February 2009.
3) I wont be giving the answer, because I do not want everyone just to sit back and think they can wait for my reply.
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GOOD LUCK
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PHASE 1 SIM Card
3F00
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Response: 00 00 1A 47 3F 00 00 00 F1 F4 44 13 15 83 02 03 04 00 82 8A 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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Allocated memory :1A47File ID :3F00
Type of file :MFNumber of DF : 2
Number of EF : 3 Number of CHV's : 4
CHV1(PIN1) :Disabled
CHV1(PIN1) Status :2 Tries left
CHV1(PIN1) Status :10 Tries left
CHV1(PIN1) Status :0 Tries left
CHV1(PIN1) Status :0 Tries left
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3F00:0000
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Response: 00 00 00 18 00 00 00 00 FF FF FF 13 06 00 00 02 01 00 00 0A FF
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File ID :0000
Type of file :RFU
Structure of file :Transparent
File Size :0018
Read Access :CHV (PIN) 15
Write Access :CHV (PIN) 15
Increase Access :CHV (PIN) 15
Rehabilitate :CHV (PIN) 15
Invalidate Access :CHV (PIN) 15
File Status :Not Invalidated
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Phase 2 SIM Card
3F00
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Response: 00 00 63 9C 3F 00 01 FF FF FF FF 01 0E 93 02 07 02 00 83 8A 00 00 00 00 83 00 FF
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Allocated memory :639C
File ID :3F00
Type of file :MF
Number of DF : 2
Number of EF : 7
Number of CHV's : 2
CHV1(PIN1) :Disabled
CHV1(PIN1) Status :3 Tries left
CHV1(PIN1) Status :10 Tries left
CHV1(PIN1) Status :0 Tries left
CHV1(PIN1) Status :0 Tries left
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3F00:0000
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Response: 00 00 00 12 00 00 04 00 FA FF FF 01 02 00 00
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File ID :0000
Type of file :EF
Structure of file :Transparent
File Size :0012
Read Access :CHV (PIN) 15
Write Access :CHV (PIN) 10
Increase Access :CHV (PIN) 15
Rehabilitate :CHV (PIN) 15
Invalidate Access :CHV (PIN) 15
File Status :Not Invalidated
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Phase 3 (2+) SIM Card
3F00
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Response: 00 00 00 01 3F 00 01 00 00 00 00 00 09 81 04 12 0A 00 83 8A 83 8A
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Allocated memory :0001
File ID :3F00
Type of file :MF
Number of DF : 4
Number of EF : 18
Number of CHV's : 10
CHV1(PIN1) :Disabled
CHV1(PIN1) Status :3 Tries left
CHV1(PIN1) Status :10 Tries left
CHV1(PIN1) Status :3 Tries left
CHV1(PIN1) Status :10 Tries left
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3F00:0000
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Response: 00 00 00 17 00 00 04 00 FB FF FF 01 02 00 00
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File ID :0000
Type of file :EF
Structure of file :Transparent
File Size :0017
Read Access :CHV (PIN) 15
Write Access :CHV (PIN) 11
Increase Access :CHV (PIN) 15
Rehabilitate :CHV (PIN) 15
Invalidate Access :CHV (PIN) 15
File Status :Not Invalidated
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Tuesday, December 02, 2008
Another ultra-thin membrane device



Tuesday, November 18, 2008
Ultra-thin membrane changes (U)SIM card usage
Examiners may come across an ultra-thin (0.3mm) membrane that lays over the contacts of a SIM card. Called the V200 SIM Dialer, the membrane is "Prefix base programmable (For routing prefix and bypass prefix setting)". What does that mean? Well, it allows mobile phones installed with SIM Tool Kit menu (most up to date phones have them) and define access to the network. The point being, if you are looking for least-cost routing for calls or want to use a calling card, rather than have mobile network call charges, then this device makes that happen, apparently.
How does it do it? "Dial the desired number directly each time you call, SIM dialer V200 will automatically dial IP access in front of the dialed number". As the manufacturer promotes, using their device will not change your dialling habits and there is "No cutting, No pounching your SIM".
As the device has been programmed, and looking at the on-board chip, there should be a reader for it or one could be constructed. This throws me back to the old days of ponyprog and PIC basics. Of course, of equal importance is how does this device impact when examining the handset and SIM card? Will manual examination be the only course for examination or do the current handset and SIM readers detect changes this device makes to them? What evidence is there for call history or data usage? These are just a few of the questions to get examiners started.

It seems this programmable ultra-thin membrane is not limited to just SIM calls, but there is a USIM version (U-SIM V33G) that can be used to unlock iPhones. There is a video that is useful to watch so that examiners can at least comprehend how ultra-thin the membrane is and how it is installed:-
http://tw.youtube.com/watch?v=JQSNJxis7Ds
Saturday, November 01, 2008
Cloning Test SIM Cards
Cloning test SIM cards can present problems if their use is not carefully monitored and can lead to loss of data from a device under test (DUT). There appears many different instances under which the loss of data can occur when using a cloning test SIM card. Some examples are:
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- The inadequate level of notice and advice within the applications that create the clone test SIM card to precisely define that a particular Make/Model of handset has been tested using the cloning application before using with a partricular Make/Model or where the guide generally infers the application is usable with a particular Make.
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- Whether the cloned test SIM card has been correctly recorded or not, before inserting it into the device under examination (DUT).
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- The 'trial and error' approach being applied to evidential mobile phones leading to loss of data, where the written advice in the guide, when given, doesn't deal with the examination problem at hand.
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Taking one example of a mobile phone examination problem relating to the Samsung D880.
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This mobile phone is capable of having two SIM cards inserted, at the same time, in order to allow for two different subscriber accounts to be used separately by a user. To understand the difference compare the position when dealing with the traditional way of having to manually swop a SIM card with another in a device that is a single-inserted SIM card operating mobile phone.
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Once the user has selected to use one of the two SIM Cards inserted, the option to switch to a particular SIM in normal user mode is via the 'SIM selection key' with visual Icons displayed on the device's screen confirming which SIM and subscription account is in use.
Problematical for the examiner using cloned test SIM cards is what is the safest method for examining a dual SIM card mobile phone. Looking at some options, what problems can arise for the examiner:
1) Take out one of the user SIM cards and produce a cloned test SIM card, whilst leaving the other user SIM card in place? Then insert the new clone test SIM card and then examine the phone? It is unlikely this could work well because an original user SIM card is still in place, thus the mobile phone could still register to the network etc. That is so, because the examiner doesn't know which SIM and subscription account was last used by the mobile phone. The notion of switching the mobile phone 'ON' prior to using a cloned Test SIM card to find out begs the question why is the examiner using cloned test SIM cards in the first place?
2) Take out both user SIM cards and produce two cloned test SIM cards, but insert only one test card and examine on that basis? This might work, provided of course the examiner has selected for access the right SIM slot and subscription account, which is a bit 'trial and error', 'hit and miss'? Moreover, assuming the above method had worked and the examiner safely selected the correct SIM slot/account - for example by taking the pragmatic step of recording which user SIM came out of which slot and replacing the correct cloned test SIM card into the slot - what happens when the second cloned test SIM card needs to be inserted? Using the SIM selection key to switch to another SIM card may not assist because there isn't a cloned test SIM card in the second slot for the device to read any details. Moreover, bearing in mind the device memory has noted only one SIM inserted the first time around what impact might now happen if a second cloned test SIM card is inserted? Will it allow access to the subscriber account user data on the device? Furthermore, what happens when switching over to the other cloned test SIM card?
3) Inevitably, the line of reasoning in this discussion is intended to bring the reader's attention to the option of putting both cloned test SIM cards into the appropriate SIM slots and examining further from that standpoint. But what happens then if the device does not give up its riches and enables the examiner to gain access to the user data? Turning to the cloned test SIM cards guides, what if they provide no assistance at all? What if the cloning application may not record properly to the cloned test SIM card or the data that it does record are insufficient for a particular make and model of mobile phone to function in the way it is expected?
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In each of the above cases where loss of data might occur, that is to say e.g. where no call history or text messages are accesible, it may not be because the user has deleted them or the user has gone to settings to set a calendar event to delete texts or clear call history on a date and time, but may be because the cloned test SIM card may have removed access to them and the examiner may not be aware of that until either using a device reading program or conducting manual examination.
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The presumption suggested that the examination and the tools used to recover data from a device were functioning properly and without flaw at the time of the examination arising from the mobile phone data being served in evidence, inferring that it is safe to rely on, may not meet the maxim omnia praesumuntur rite esse acta, as expressed by Lord Griffiths in the case of R .v. Shepherd [1993] AC380. That can be so because it has never simply been solely about whether the original device (exhibit) was working properly at the material time, but of equal significance whether in the obtaining and the processes used to obtain data that the evidence is safe to rely on. The latter requirement did not disappear in the wake of the repeal of section 69 Police and Criminal Evidence Act 1984. Nor did it disappear by the introduction of the Criminal Procedures and Investigations Act 1996, The Police Act 1997, The Regulation of Investigatory Powers Act 2000 and so on.
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The purpose of raising this discussion (for examiners and students) about mobile phone forensic examination and tools it that discussions on these types of topics are not simply about providing answers and solutions to problems, but identifying potential questions that need to be adddressed before using cloned test SIM cards.
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Lastly, I have not described every event dealing with the examination of a dual SIM card mobile phone or how Samsung D880 manages the operation and functionality of both SIM cards. By not referring to these matters it has helped simplify and refine the discussion to keep the important points to the fore.



