So I got Fairphone 4, with /e/ os, a couple of days ago. When I connected it to my NextDNS I saw that it was trying to connect to some weird addresses, like every 5-10 minutes. I searched Internet a bit and found out that it was something with snapdragon cpu and location services. I travel a lot and use Organic Maps for navigation, so location was enabled almost all day on the phone. I turned off location services and connections stopped, and everything was fine for a couple of days.

Today I came home, checked logs in NextDNS and saw that phone started doing the same connections almost constantly even with location turned off.

Can I do something about this, other than allowing these connections? These connections are probably so numerous because they are getting blocked. If I allowed them, phone would maybe call home once in a couple of hours. I would rather not allow them, but I don’t want 20% of battery to be eaten by this.

  • Skull giver@popplesburger.hilciferous.nl
    2·
    1 year ago

    The IME is active, but only for the bare necessities. Modern Intel CPUs simply will not bootstrap without the IME firmware. I know the thing runs Minix, but so far nobody who has reverse engineered it has found any serious threats when the management service isn’t running.

    You can zero out some unnecessary components of the BIOS firmware so it can’t do networking and run daemons, but you need at least the ROMP and BUP partition.

    Motherboard manufacturers can also toggle a bit that request the IME to be disabled after it finishes its critical initialisation code (I believe governments really like this feature) but you’d still be relying on Intel’s encrypted code. If you have a BIOS flasher (or a Raspberry Pi and some soldering skills or the right programming clip for your motherboard), you can make a backup of the BIOS and then enable the bit yourself.

    I don’t know the source of your phantom MAC address. I’ve never seen an Intel ME DHCP request on my network. As far as I know, the Intel ME is supposed to take the same IP address as the host, unless you’re using a PCIe network adapter. The IME integrates with the Intel network card and extracts packets that it likes to operate on.

    There is a Windows tool that will tell you your Intel ME MAC address if you want to confirm (MEInfoWin) if you want to confirm. It’s not a public tool that consumers are supposed to have access to, but you can find it (accidentally) distributed with firmware updates for motherboards.

    • MigratingtoLemmy@lemmy.world
      2·
      1 year ago

      Thanks for your comment, much appreciated! Could you provide a source for someone who has reverse-engineered a recent version of ME and has found not much incriminating behaviour for consumer motherboards?

      Unfortunately, me_cleaner doesn’t seem to work too well with newer chips. Fortunately for me, I’m planning to purchase older computers, but for people who aren’t, this doesn’t help much (as far as I can see).

      Thank you for the idea of extracting the BIOS to enable the HAP bit. Won’t it require some serious reverse-engineering chops to find the HAP bit and enable it inside of such a binary blob? I’m not really used to Ghidra yet haha.

      If I remember correctly, ME uses its own MAC address, but the same IP address of the host. Or maybe this is no longer the case. How would it extract packets though? Won’t that require serious compute power? Or does it look for packets with specific labels identifying them?

      Thanks for letting me know about MEinfoWIN. I’ll try and find it!

      • Skull giver@popplesburger.hilciferous.nl
        3·
        1 year ago

        Could you provide a source for someone who has reverse-engineered a recent version of ME and has found not much incriminating behaviour for consumer motherboards?

        It’s hard to prove a negative, but with people doing deep dives like these not finding any malicious behaviour yet, I doubt there’s anything of note happening in the ME on consumer hardware.

        Theoretically the NSA could backdoor the IME, but if they can backdoor the ME firmware, they can also backdoor the tiny Pentium processor inside every Intel CPU, or the UEFI ROM, the microcode, or any other firmware really. In practice they plant tiny their own chips onto existing motherboards, which can be easily removed so they don’t leave a trace.

        Won’t it require some serious reverse-engineering chops to find the HAP bit and enable it inside of such a binary blob?

        It looks like the HAP bit has changed location (someone already found out the new offset) but me_cleaner has built in support for setting the bit in many cases; this commit from this PR seems to implement that. Disabling the firmware does, as you would expect, disable the firmware loading process though, meaning Intel Audio won’t work right and booting becomes weirdly slow. You also lose fTPM support and modern sleep (S0ix).

        How would it extract packets though? Won’t that require serious compute power? Or does it look for packets with specific labels identifying them?

        The packets enter the Intel network card, and the network card pre-processes them in a bunch of ways (validating checksums, sometimes even reassembling fragmented frames). Modern network cards are fully aware of IP and in limited fashion TCP, so “extract traffic towards port 664/16993/16995 and do not notify the OS” isn’t that hard to accomplish.

        A separate MAC with the same IP would cause tons of conflicts on the network, I don’t think Intel would (intentionally) use that approach.

        • MigratingtoLemmy@lemmy.world
          2·
          1 year ago

          Thank you, that clears it up. I’m not as informed on this matter as I used to be in the past, apologies for any assumptions I might have made.

          Thanks for the link and the link to the PR, I might try this with a PC or two in time. Do I need Intel Audio for Pipewire to work? I didn’t quite grasp the ramifications of certain parts of the firmware not working such as Audio and Sleep; would I need to find a software solution for Sleep? Also, will this affect C-states by any chance?

          That makes a lot of sense. Maybe I was looking at something different in my network at that point. Thanks again!

          • Skull giver@popplesburger.hilciferous.nl
            2·
            1 year ago

            Thank you, that clears it up. I’m not as informed on this matter as I used to be in the past, apologies for any assumptions I might have made.

            No worries, I only about this stuff because I recently saw a Defcon talk about it on youtube and started Googling. I could be wrong about some of it to be honest, there’s a lot of uncertainty here.

            Do I need Intel Audio for Pipewire to work?

            If you use the headphone jack of your PC or a laptop’s integrated speakers: yes. If you don’t care, not really. You can always make a backup of the ROM chip first so you can restore it if you find any problems.

            would I need to find a software solution for Sleep?

            That depends. Some motherboards still have firmware for S3 sleep, that should work just fine I believe. S0ix is a bit weird in that it “sleeps” the same way your smartphone does, waking up occasionally to do things like download updates or do other background tasks. Quite useful for PCs left in sleep mode overnight, not great when the drivers are bugged and tell your laptop’s CPU to wake up in your backpack.

            Also, will this affect C-states by any chance?

            I don’t think so, but I’m not sure.

            • MigratingtoLemmy@lemmy.world
              1·
              1 year ago

              Thanks. I was planning to use a USB connection to a DAC for audio, but I’d like to be able to use the speakers on my monitor too, if possible. I’ll be using a desktop computer.