Security Leftovers

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How to hide a backdoor in AI software – such as a bank app depositing checks or a security cam checking faces
Boffins in China and the US have developed a technique to hide a backdoor in a machine-learning model so it only appears when the model is compressed for deployment on a mobile device.
Yulong Tian and Fengyuan Xu, from Nanjing University, and Fnu Suya and David Evans, from University of Virginia, describe their approach to ML model manipulation in a paper distributed via ArXiv, titled "Stealthy Backdoors as Compression Artifacts."
Machine-learning models are typically large files that result from computationally intensive training on vast amounts of data. One of the best known at the moment is OpenAI's natural language model GPT-3, which needs about 350GB of memory to load.
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Matthew Garrett: More doorbell adventures
Doorbird sell a chime, a network connected device that is signalled by the doorbell when someone pushes a button. It costs about $150, which seems excessive, but would solve my problem (ie, that if someone pushes the doorbell and I'm not paying attention to my phone, I miss it entirely). But given a shell on the doorbell, how hard could it be to figure out how to mimic the behaviour of one?
Configuration for the doorbell is all stored under /mnt/flash, and there's a bunch of files prefixed 1000eyes that contain config (1000eyes is the German company that seems to be behind Doorbird). One of these was called 1000eyes.peripherals, which seemed like a good starting point. The initial contents were {"Peripherals":[]}, so it seemed likely that it was intended to be JSON. Unfortunately, since I had no access to any of the peripherals, I had no idea what the format was. I threw the main application into Ghidra and found a function that had debug statements referencing "initPeripherals and read a bunch of JSON keys out of the file, so I could simply look at the keys it referenced and write out a file based on that. I did so, and it didn't work - the app stubbornly refused to believe that there were any defined peripherals. The check that was failing was pcVar4 = strstr(local_50[0],PTR_s_"type":"_0007c980);, which made no sense, since I very definitely had a type key in there. And then I read it more closely. strstr() wasn't being asked to look for "type":, it was being asked to look for "type":". I'd left a space between the : and the opening " in the value, which meant it wasn't matching. The rest of the function seems to call an actual JSON parser, so I have no idea why it doesn't just use that for this part as well, but deleting the space and restarting the service meant it now believed I had a peripheral attached.
The mobile app that's used for configuring the doorbell now showed a device in the peripherals tab, but it had a weird corrupted name. Tapping it resulted in an error telling me that the device was unavailable, and on the doorbell itself generated a log message showing it was trying to reach a device with the hostname bha-04f0212c5cca and (unsurprisingly) failing. The hostname was being generated from the MAC address field in the peripherals file and was presumably supposed to be resolved using mDNS, but for now I just threw a static entry in /etc/hosts pointing at my Home Assistant device. That was enough to show that when I opened the app the doorbell was trying to call a CGI script called peripherals.cgi on my fake chime. When that failed, it called out to the cloud API to ask it to ask the chime[1] instead. Since the cloud was completely unaware of my fake device, this didn't work either. I hacked together a simple server using Python's HTTPServer and was able to return data (another block of JSON). This got me to the point where the app would now let me get to the chime config, but would then immediately exit. adb logcat showed a traceback in the app caused by a failed assertion due to a missing key in the JSON, so I ran the app through jadx, found the assertion and from there figured out what keys I needed. Once that was done, the app opened the config page just fine.
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Security updates for Thursday
Security updates have been issued by Debian (python-django), Fedora (java-latest-openjdk, libopenmpt, python-yara, skopeo, thunderbird, and yara), openSUSE (ceph and openexr), Red Hat (postgresql), SUSE (libxml2), and Ubuntu (exim4 and gnome-autoar).
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Peloton User Accounts Subjected to Data Leaks
Fitness is supposed to be difficult – it’s how you know it’s working (or at least that’s what we’re told). But it shouldn’t be difficult in this way. A security researcher discovered that the user accounts of Peloton fitness bikes and treadmills were subject to data leaks, and the company took no action initially.
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digiKam 7.7.0 is released
After three months of active maintenance and another bug triage, the digiKam team is proud to present version 7.7.0 of its open source digital photo manager. See below the list of most important features coming with this release.
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Dilution and Misuse of the "Linux" Brand
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Samsung, Red Hat to Work on Linux Drivers for Future Tech
The metaverse is expected to uproot system design as we know it, and Samsung is one of many hardware vendors re-imagining data center infrastructure in preparation for a parallel 3D world.
Samsung is working on new memory technologies that provide faster bandwidth inside hardware for data to travel between CPUs, storage and other computing resources. The company also announced it was partnering with Red Hat to ensure these technologies have Linux compatibility.
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today's howtos
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