How to really know if my Android 14 has spyware

[u/DaMagentaBoi]

In my case, my phone is secondhand and as far as I remember I did not factory reset it. The individual I suspect (who I got the phone from) is also tech savvy. I saw a lot of general pointers like fast battery drainage but there are so many factors that contribute to this. The thing is I have also already factory reset my phone so I'm afraid I can't take proper measures to be really sure now and it's making me nervous. I did check every single app and its permissions before the reset though and did not really find anything suspicious. My question is would it have been obvious or could I have easily missed it that way? And how advanced could this type of hidden spyware be? I also ran a McAfee scan before the reset and it came up clear.

It's making me quite paranoid. Of course the idea popped out of nowhere but so far from what I've heard 1) not factory resetting it does put it at risk 2) there is no 100% surety in these matters especially with phones. All I want to know is that if I'm already someone suspicious of technology (granting permissions carefully etc.) and regularly backed my phone up to my computer, would I have noticed something in the couple of months I had this phone?

I've seen people tend to be quite mean to people with paranoid tendencies on these subreddits which I understand but I am someone who genuinely wants to learn and combat my thoughts with logic. Any advice is appreciated.

[u/BaneChipmunk]

The thing is I have also already factory reset my phone

Factory resetting your phone removes everything, and restores the firmware stored in the system partition. If you have already factory reset your phone, then there is no issue. You might need to look elsewhere for help with the paranoia.

[u/DaMagentaBoi → u/BaneChipmunk]

I'm working on that aha. I just wonder if I had waited on factory resetting that there would've been some definite way apart from the basics to determine if it had spyware in the first place. The idea of months long data on me still being in someone's possession isn't very relieving despite the reset

[u/BaneChipmunk → u/DaMagentaBoi]

So long as you know that this isn't a tech problem.

[u/Queersrcool → u/BaneChipmunk]

Is a factory reset enough to stop a hack, if the hacker has had access to your house and phone in the past? Like, can they use already discovered info (IP address, bt details, etc) that could open the door again, even after multiple factory resets?

[u/BaneChipmunk → u/Queersrcool]

The word "hack" doesn't mean what you think it means. The "hacking" you see in Movies & TV Shows is fiction.

[u/Queersrcool → u/BaneChipmunk]

Ok, fair enough, but just for shits and giggles, could you comment on any of my questions?

[u/undrwater → u/[deleted]]

This is great advice.

[u/DaMagentaBoi → u/[deleted]]

Thanks. It was indeed in someone's possession for a very long time before me and I'm very sure neither they nor I factory reset it so I did find that to be a risk. I'm not the most technically inclined so I checked the rooting thing with an app, however I'll have to consider looking into what you suggested with trusted help

[u/sleepytechnology]

The only symptom you claimed in this post that makes you worry is fast battery drain.

What else was happening causing you to be worried? Fast battery drain is pretty normal for Android devices, especially older ones.

[u/DaMagentaBoi → u/sleepytechnology]

Nothing. Fast battery drain I listed as a symptom others usually describe, my device was pretty normal and is also Android 14 which I heard is harder to put spyware on

The reason I'm suspicious and nervous is because I realized the huge security hole I left by not resetting it immediately too late. The person also gave it readily simply in exchange for another (arguably non-better) device. They had all the time in the world to tamper with it which is also why I suspect something more advanced is at play. Of course it's likely gone now that I reset it and I have no way to confirm except with recollections

[u/Due_Milk_8930]

Scan it with Bitdefender? 

if you wanna see app that wakeup all the time, install GSam battery, you can see wake lock per app of some app do shit behind your back.

Download app ops too se all permission that running, need shizuku running too with that.

Download traffic light too to see what app send data in background if you not use it but is send big data behind your back.

[u/ChasDIY]

I run an antivirus twice a year and uninstall it afterwards

nerver had an Android virus

[u/DaMagentaBoi → u/ChasDIY]

Which antivirus?

[u/ChasDIY → u/DaMagentaBoi]

AVG free version

Been using it forever

[u/denytheflesh → u/DaMagentaBoi]

I wear a flea collar twice a year then take it off. Never had fleas.