I am reading a news article (in italian) in which the police snooped on the Dean of a university by a trojan horse that the police had installed on his mobile phone.

In particular, the trojan horse transmitted face-to-face conversations (I think captured by the microphone of the mobile phone) to the police.

In another case some time ago (link, english, link english) the police were able to snoop face-to-face conversations between people by installing a trojan horse on the mobile phone of the suspect (and since there are transcripts of the conversation, I think the microphone capture those conversations).

In fact a police officer (link, italian) declared that "We don't use wiretaps anymore. We just install a software on the suspect's mobile phone and turn on the microphone".

How do governments get a trojan horse installed on suspect's mobile phones in the first place?

If you run Android, can they have for example agreement with Google that would have the trojan horse downloaded and installed automatically?


4 Answers 4


The police are not going to tell anyone exactly how they do something. And not every police force will do the same thing.

The options are:

  • exploit a vulnerability (just like the NSA's catalog of options)
  • supply chain infiltration ("download the latest update to your super-secret encrypted chat app!")
  • social engineering ("pssst. wanna do crime? install this and make big $$$").

I have seen articles over the years where different law enforcement agencies have done all 3 of those things.

  • How would the "supply chain infiltration" work in the case of Android? There would have to be an app on the Play Store controlled by the police. An update to that app would install the trojan on all persons that have downloaded that app Commented Mar 14, 2021 at 11:41
  • 2nd point: would a voluntarily coded backdoor for the police in OS code fall under "exploit a vulnerability"? Commented Mar 14, 2021 at 11:41
  • An app designed by a 3rd party, even a criminal supplier, that is then taken over by law enforcement and a backdoor inserted into an update.
    – schroeder
    Commented Mar 14, 2021 at 14:07
  • Intentional vulnerabilities are a possibility for exploitation, yes.
    – schroeder
    Commented Mar 14, 2021 at 14:08

Governments and official security forces use government hacking companies such as HackingTeam and the list goes on.

This software relies on 0-day exploits mainly to do that.

  • Can a 0-day allow to install an app without the user doing anything (like clicking on a link)? Commented Mar 14, 2021 at 11:43
  • @raffaem Yes, it can. See for example the Broadpwn exploit against Broadcom wifi chipsets. blog.exodusintel.com/2017/07/26/broadpwn
    – Mike Scott
    Commented Mar 14, 2021 at 11:50

The most likely way a Trojan could be installed on a phone is if a user clicks on a malicious link. It would probably come in the form of a text message or email. Additionally, if you don't install updates (especially security updates), then that greatly improves the chances that one could be successfully installed.

Most law enforcement agencies don't have the capabilities to develop hacking tools themselves, so they rely on commercial hacking software and forensic toolkits. I would doubt that Google would allow a foreign law enforcement agency to use their app store to install a malicious app on a user's phone.




  • "Most law enforcement agencies don't have the capabilities" -- I think you mean "local police". The FBI, Europol, etc. certainly have the capability. And your example is "exploit a vulnerability" and "social engineering". So, what I said ...
    – schroeder
    Commented Mar 14, 2021 at 11:23
  • 1
    @schroeder FBI and the like certainly don't have the expertise to develop the tools themselves. They always rent the capabilities.
    – forest
    Commented Mar 14, 2021 at 11:35
  • @forest it appears that you and I move in very different circles. Yes, sometimes they rent when it's efficient to do so. But, yes, they do have capability ...
    – schroeder
    Commented Mar 14, 2021 at 14:05
  • @schroeder Perhaps they have the ability to develop basic malware, but they really have limited in-house expertise when it comes to developing advanced exploits (which is what I imagined when the post said "hacking abilities"). The FBI simply does not pay enough to retain people with very good exploit development skills. People who do develop such skills almost always end up moving to the private sector (even if they're still selling bugs to feds).
    – forest
    Commented Mar 14, 2021 at 23:13
  • The NSA certainly has exploits, rootkits and trojan horses, see TAO Commented Mar 17, 2021 at 0:20

The police go through the service provider . The service provider can very easily monitor every single thing you do through that phone .

A phone is basically a tracking and monitoring device in your pocket .

Turn it on airplane mode

  • No, a service provider can't. Because of all the encryption that has been put in place for years to prevent exactly that. If they could, then the OP's links about needing to install a trojan would not be necessary ...
    – schroeder
    Commented Dec 22, 2022 at 9:16

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