TAG | cellular
When you think your phone is connected to your wireless provider, you might actually be connected to a rogue tower set up to capture your data.
Such devices have been demonstrated at the Black Hat security conference and a law enforcement fake tower called “Stingray” has been known for some time. Recently sophisticated secure phones have been able to detect these fake towers and people are starting to map them. Popular Science covered it here, and here.
There is very little transparency around law enforcement or US Intelligence use of such devices, so the could just as easily be operated by foreign intelligence services, criminals, or hackers. If we had strong end to end encryption there would be little to worry about, but many Internet connections and all phone calls are vulnerable to this attack.
In a unanimous decision, the Supreme Court ruled that police must obtain a warrant before searching suspect’s cellphone. Before this, cellphones were treated just like anything else a suspect might carry, including wallet, keys, address book, or various other “pocket litter”.
Police are generally allowed to search suspects for weapons and to prevent the distraction of evidence. Because of the massive amount of storage on a modern smartphone, and its direct connection into so many other stores of data and communications, the court felt that the contents of these devices was qualitatively different and deserving of greater protection.
It is important to remember that the police can still take the phone, and that they can then get a warrant to search it if there is probable cause. They are simply prevented from searching it without the warrant, possibly in the hope (but not expectation) of finding evidence.
This decision may lay the groundwork for according similar protections to cloud stored data, which once would have been kept in the home in hard copy. Law enforcement officials claim that technology is making life easier for criminals and harder for law enforcement. I find that hard to believe and have not seen any really good studies of the matter. If you have, please let me know!
It strikes me that the routine preservation of emails and other communications, along with the massive use of server logged communications from text messages to social media, actually makes things much easier for law enforcement on the whole.
The fact that the decision was unanimous suggests that we may be entering a period of re-evaluating outdated precedents from the pre-internet era.
Some key quotes from the decision:
- Regarding treating phones like other pocket litter – “That is like saying a ride on horseback is materially indistinguishable from a flight to the moon,”
- On the impact on law enforcement – “Privacy comes at a cost.”
- “Cell phones differ in both a quantitative and a qualita- tive sense from other objects that might be kept on an arrestee’s person. The term “cell phone” is itself mislead- ing shorthand; many of these devices are in fact minicom- puters that also happen to have the capacity to be used as a telephone. They could just as easily be called cameras, video players, rolodexes, calendars, tape recorders, librar- ies, diaries, albums, televisions, maps, or newspapers.”
- “The scope of the privacy interests at stake is further com- plicated by the fact that the data viewed on many modern cell phones may in fact be stored on a remote server. Thus, a search may extend well beyond papers and effects in the physical proximity of an ar- restee, a concern that the United States recognizes but cannot defini- tively foreclose.”
- “Our answer to the question of what police must do before searching a cellphone seized incident to an arrest is accordingly simple—get a warrant,”
Some Excellent Articles for further reading:
Note: In the picture above, the policeman is actually just using his own cellphone.
The city of Chicago is getting ready to deploy several monitoring stations on light poles along Michigan Avenue. In addition to collecting environmental information like sound volume, light intensity, and air quality, the devices will also count people by detecting wireless signals from passing mobile devices.
The system is designed to only count devices without capturing unique identifiers. While this may be true, it would certainly be easy to change in the future with only a tiny tweak to the software.
This set up looks similar to the tracking trashcans I discussed last year.
Capturing this kind of data is inevitable, and would be invisible if the city had not announced its intentions. The key will be to ensure appropriate protections for collected information, whoever does the collecting. It is refreshing that all of the data captured as part of this project will be published immediately. Assuming nothing is held back that will give a clear sense of exactly what kinds of information can be extrapolated from the raw data.i
Additionally architectural changes like the random MAC addresses in iOS 8 can significantly improve privacy in the face for such monitoring and tracking.
A federal appeals court in Atlanta ruled that there is an expectation of privacy in cell tower location information, and therefor it is protected by the Fourth Amendment. This runs counter to other recent rulings that allow access to the information without a warrant under the Stored Communications Act.
The recent ruling relies on precedent from the 2012 Supreme Court decision in United States vs. Jones which stated that a warrant was required to place a tracking device on a suspects car. Phone records provide the same information, just with a different technical means.
This would not apply to intelligence gathering activities, nor would it prevent access to your location information with a warrant. It is a move to recognize that our personal information, about which we have real privacy interests, is increasingly existing in the networks of third parties. Laws that assume anything sensitive would be on paper and stored in your house or on your person are absurdly outdated.
For now this is only a local precedent. The issue will almost certainly end up in the Supreme Court at some point.
OS News has an interesting article: The second operating system hiding in every mobile phone
It discusses the security implications of the fact that all cell phones run two operating systems. One is the OS that you see and interact with: Android, iOS, Windows Phone, BlackBerry, etc. The other is the OS running on the baseband processor. It is responsible for everything to do with the radios in the phone, and is designed to handle all the real time processing requirements.
The baseband processor OS is generally proprietary, provided by the maker of the baseband chip, and generally not exposed to any scrutiny or review. It also contains a huge amount of historical cruft. For example, it responds to the old Hays AT command set. That was used with old modems to control dialing, answering the phone, and setting up the speed, and other parameters required to get the devices to handshake.
It turns out that if you can feed these commands to many baseband processors, you can tell them to automatically and silently answer the phone, allowing an attacker to listen in on you.
Unfortunately the security model of these things is ancient and badly broken. Cell towers are assumed to be secure, and any commands from them are trusted and executed. As we saw at Def Con in 2010, it is possible for attackers to spoof those towers.
The baseband processor, and its OS, is generally superior to the visible OS on the phone. That means that the visible OS can’t do much to secure the phone against these vulnerabilities.
There is not much you can do about this as an end user, but I thought you should know. 🙂
Based on a single line in a Washington Post article, Privacy International has been investigating whether it is possible to track cell phones when they have been turned off. Three of the 8 companies they contacted have responded.
In general they said that when the phone is powered down that there is no radio activity, BUT that might not be the case if the phone had been infected with malware.
It is important to remember that the power button is not really a power switch at all. It is a logical button that tells the phone software that you want to turn the phone off. The phone can then clean up a few loose ends and power down… or not. It could also just behave as though it were shutting down.
They don’t cite any examples of this either in the lab or in the wild, but it certainly seems plausible.
If you really need privacy, you have two options (after turning the phone “off”):
1) If you can remove the phone’s battery, then doing so should ensure that the phone is not communicating.
2) If you can’t remove the battery (hello iPhone) then you need to put the phone in a faraday cage. You can use a few tightly wrapped layers of aluminum foil, or buy a pouch like this one.
ArsTechnica has a nice article on a recent ruling by the US Fifth Circuit court of appeals.
In this 2-1 decision, the court ruled that cellular location information is not covered by the fourth amendment, and does not require a warrant. The logic behind this ruling is that the information is part of business records created and stored by the mobile phone carriers in the ordinary course of their business.
Therefor, the data actually belongs to the phone company, and not to you. The Stored Communications Act says that law enforcement must get a warrant to obtain the contents of communications (the body of emails or the audio of a phone call) but not for meta-data like sender, recipient, or location.
The court suggests that if the public wants privacy of location information that they should demand (I suppose through market forces) that providers delete or anonymize the location information, and that legislation be enacted to require warrants for access to it. Until then, they say we have no expectation of privacy in that information.
The Fifth Circuit covers Louisiana, Mississippi, and Texas.
This ruling conflicts with a recent New Jersey Supreme Court, which unanimously ruled that law enforcement does not have that right, which ruling only applies in New Jersey.
Montana has a law requiring a warrant to obtain location information, while in California a similar bill was vetoed.
It seems very likely that one or more of these cases will go to the supreme court.
The ACLU just posted an article about a recent federal magistrate judge’s ruling. It is a somewhat bizarre case.
The DEA had an arrest warrant for a doctor suspected selling prescription pain killer drugs for cash. They then requested a court order to obtain his real time location information from his cell provider.
The judge went along, but then published a 30 page opinion stating that no order or warrant should have been required for the location information because the suspect had no expectation of location privacy. If he wanted privacy, all he had to have done is to turn off his phone (which would have prevented the collection of the information at all, not just established his expectation).
So, if this line of reasoning is picked up and becomes precedent, it is clear than anyone on the run needs to keep their phone off and / or use burner phones paid for with cash.
My concern is that, if there is no expectation of privacy, is there anything preventing government entities from requesting location information on whole populations without any probable cause or court order.
While I think that the use of location information in this case was completely appropriate, I would sleep better if there was the check and balance of the need for a court order before getting it.
This is another situation where technology has run ahead of the law. The Fourth Amendment was written in a time where information was in tangible form, and the only time it was generally in the hands of third parties, was when it was in the mail. Therefor search of mail in transit was specially protected.
Today, cloud and telecommunication providers serve much the same purpose as the US Postal Service, and are used in similar ways. It is high time that the same protection extended to snail mail be applied to the new high tech communications infrastructures we use today.
The story is about a german politician Malte Spitz who sued to obtain the retained cell tower records for his own phone, then provided them to the newspaper. The newspaper has created a nice map and timeline tool to allow you to play Spitz’s movements over 6 months. The resolution is impressive and should be a real wake up call about the level of detailed information being gathered on us all.
Of course, if the phone company was capturing GPS or WiFi based location information the data would be much more accurate. While GPS would quickly drain the battery, many modern phones have WiFi enabled all the time, so that information would be readily available without any additional impact on the phone’s performance.