November 2022 - wlug - list.wlug.org.nz

List Of IPTV Resources
by Lawrence D'Oliveiro 22 Sep '24

22 Sep '24

This user <https://github.com/iptv-org> just popped up in my GitHub feed. One repo <https://github.com/iptv-org/iptv> claims to be a list of links to over 8000 streaming TV channels from nations all over the world, while the other is a list of tools*, providers and other resources. Do be aware it’s a bit of a mixed bag: yes, there are legitimate channels (no encryption so far that I have noticed), but also some dubious-looking links. *Oddly, FFmpeg and youtube-dl aren’t in the list.

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Enabling Case-Insensitive Filenames On Linux
by Lawrence D'Oliveiro 06 Feb '24

06 Feb '24

The ext4 filesystem has had the “casefold” option for a while now <https://lwn.net/Articles/784041/>. This allows you to specify, when you initialize a new filesystem, that you want file/directory names to be treated as case-insensitive. At the same time, you have to specify that the filenames are to be interpreted as UTF-8 encoding; normally the kernel doesn’t care, it only singles out ASCII slash and NUL bytes for special interpretation, and simply passes through any other byte values in the names. I was able to create such a filesystem, but I wasn’t able to mount it in my last-upgraded-just-a-few-days-ago Debian Unstable setup. When I try, it fails, and in the dmesg log I see Filesystem with casefold feature cannot be mounted without CONFIG_UNICODE Turns out the Debian 5.10 kernel has not been built with this CONFIG_UNICODE option enabled. However, this situation looks set to change shortly, according to <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=985689>.

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Weta Digital’s Technology Division Sold To US Firm
by Lawrence D'Oliveiro 30 Nov '23

30 Nov '23

Let me see if I understand this article <https://www.nzherald.co.nz/business/sir-peter-jackson-to-sell-weta-digital-…> correctly: the part of Weta Digital that used to develop the in-house 3D graphics/effects tools that they use in all those movies is being sold to US-based Unity Software. The part that is left will be called “WetaFX”, and will become a customer of Unity for the use of those tools, no longer doing its own development in-house. By the way, I’ve been looking at the Unity site <https://unity.com/>, and it looks like all their products are rentware (subscription-based).

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Microsoft’s File-Tainting System ’Tain’t Working
by Lawrence D'Oliveiro 15 Mar '23

15 Mar '23

Microsoft has a clever-sounding system for trying to protect Windows users from downloading malicious files: it’s called “Mark-Of-The-Web”. What it means is that any file downloaded from an untrusted source is supposed to have a special flag set in its NTFS metadata indicating that the file is not to be trusted. So any attempt by the user to perform sensitive operations on that file (e.g. execute macros from it, run it as an executable) is supposed to trigger appropriate system warnings. If the file is a .zip archive, then this mark is supposed to be propagated to all files extracted from that archive. However, it turns out this mechanism can be bypassed (surprise, surprise) <https://www.theregister.com/2022/11/01/microsoft_motw_malware_flaw/>. How can this happen? The flaw lies in the mechanism used to tell Windows to trust downloaded files, by attaching an “Authenticode” signature to them. Files without such signatures are of course untrusted and will trigger the appropriate warnings. However, by attaching an invalid signature of a particular form, you can trigger an error response from the signature-checking process that is actually interpreted as “this file is OK” <https://blog.0patch.com/2022/10/free-micropatches-for-bypassing-motw.html>. What do you call it when an attempt to add mechanisms to make a system more secure actually increases the attack surface on that system? By the way, the referenced Twitter thread discussing this vulnerability <https://twitter.com/GossiTheDog/status/1579895038523609088> seems to be saying that no Mark-Of-The-Web propagation is done for files extracted from .iso disc images. And that Microsoft uses this form for distributing its own software (Visio was mentioned) precisely to avoid the hassle of going through vetting by third-party antimalware tools.

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Emacs: Comparing Two Regions From Two Files
by Lawrence D'Oliveiro 28 Feb '23

28 Feb '23

So I was compiling some useful database-related routines that I have used in various places (with MySQL and SQLite so far) over the years into a set of common modules, so that I could easily find the latest and best-tested versions of them for future projects. Then I came to a routine with two versions of a few dozen lines each, and I was trying to figure out a way of doing a diff on them without writing them out to temporary files. I have an Emacs command called “make-command-buffer”, which I can use for example to create a buffer for entering and executing shell commands, and collecting their output. It was easy enough to copy and paste both routines into the buffer, but now how do I put them both into one diff command? There is a shell feature called “here-docs”, which lets you include the standard-input data for a command directly following the command: «cmd» <<«marker» ... data ... «marker» where the «marker» is some word that does not occur in the data. But I want to have two of these, like this: diff -u <<EOD1 <<EOD2 ... version 1 ... EOD1 ... version 2 ... EOD2 You can do something like that in Perl, but it doesn’t work in the shell. Hunting around on line reminded me why: because you can only have one standard input. But in the Bash man page, there is a syntax for redirecting arbitary file descriptors, letting you have any number of heredocs. So, combining this with the ability to give a command a file name that corresponds to an already-open file descriptor, I finally got this to work: diff -u /dev/fd/8 /dev/fd/9 8<<EOD1 9<<EOD2 ... version 1 ... EOD1 ... version 2 ... EOD2

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New Attack On AI Bots: Prompt Injection
by Lawrence D'Oliveiro 11 Feb '23

11 Feb '23

A Twitter bot account run by a company that posts remote job listings was programmed to respond to tweets directed to it with general inoffensive comments touting the positive aspects of remote work. However <https://arstechnica.com/information-technology/2022/09/twitter-pranksters-d…>, some other Twitter users discovered that if they began their tweet with directives to “ignore previous instructions”, they could get the bot to say just about anything. And much hilarity ensued. Basically, the way the bot program works is it begins with some standard instructions on what to say, provided by the people who set up the account, to which is appended whatever tweet content was sent to the bot by the other user. This is then processed by the AI system to produce a response. This attack has been dubbed “prompt injection”, by analogy with “SQL injection” and other similar attacks on non-AI systems. But whereas those attacks can be blocked using basic, well-known syntactic quoting techniques, there seem to be no easy equivalents for stopping an AI paying attention to instructions it should not be obeying.

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Windows Driver-Signing Doesn’t Work
by Lawrence D'Oliveiro 14 Dec '22

14 Dec '22

Having Microsoft verify third-party drivers with a digital signature, so that Windows will block the loading of unsigned drivers, seemed like a good idea when it came in with Windows Vista. Enforcing quality control would remove a big source of crashes, as well as security loopholes. But it seems the execution falls somewhat short <https://arstechnica.com/information-technology/2022/10/no-fix-in-sight-for-…>. The system for revoking signatures for old, obsolete drivers that are discovered to have security vulnerabilities in them doesn’t seem to work very well, allowing miscreants to exploit this old code to gain control of Windows systems. This has been dubbed a “Bring Your Own Vulnerable Device/Driver” (BYOVD) attack. Microsoft’s own Vice President of “OS Security and Enterprise” continues to claim that “Windows has everything you need to block” buggy signed drivers. Yet the article’s author was unable to get the mechanism to work. And Microsoft itself appeared to have no interest in helping to fix that. It seems to me, one thing missing from the mechanism is a time limit on signature validity. By contrast, when you get SSL/TLS certs for your website, they are only valid for some fixed interval (e.g. a year for certs from traditional certificate authorities, 90 days for ones from Let’s Encrypt). This means that clients using such certificates do not need to maintain an ever-growing list of revoked ones to check against, since ones that are past their expiry date can be rejected anyway. If the cert for a Windows driver has expired, but the driver itself is still valid, Microsoft should be able to simply renew the certificate. But I guess if Microsoft’s servers are struggling just to distribute certificate revocations, having to push out renewals as well will likely just make things worse.

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LastPass: Notice of Recent Security Incident
by Peter Reutemann 01 Dec '22

01 Dec '22

'We recently detected unusual activity within a third-party cloud storage service, which is currently shared by both LastPass and its affiliate, GoTo. We immediately launched an investigation, engaged Mandiant, a leading security firm, and alerted law enforcement. We have determined that an unauthorized party, using information obtained in the August 2022 incident, was able to gain access to certain elements of our customers’ information. Our customers’ passwords remain safely encrypted due to LastPass’s Zero Knowledge architecture. We are working diligently to understand the scope of the incident and identify what specific information has been accessed. In the meantime, we can confirm that LastPass products and services remain fully functional.' -- source: https://blog.lastpass.com/2022/11/notice-of-recent-security-incident/ -- via: https://infosec.exchange/@dennisf/109434660011163159 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Used thin client PCs are an unsexy, readily available Raspberry Pi alternative
by Peter Reutemann 30 Nov '22

30 Nov '22

'"Raspberry Pi boards are hard to get, probably also next year," says Andreas Spiess, single-board enthusiast and YouTuber, in his distinctive Swiss accent. He's not wrong. Spiess says he and his fellow Pi devotees need "a strategy to survive" without new boards, so he suggests looking in one of the least captivating, most overlooked areas of computing: used, corporate-minded thin client PCs. Spiess' Pi replacements, suggested and refined by many of his YouTube commenters and Patreon subscribers, are Fujitsu Futros, Lenovo ThinkCentres, and other small systems (some or all of which could be semantically considered "thick clients" or simply "mini PCs," depending on your tastes and retro-grouch sensibilities). They're the kind of systems you can easily find used on eBay, refurbished on Amazon Renewed, or through other enterprise and IT asset disposition sources. They're typically in good shape, given their use and environment. And compared to single-board enthusiast systems, many more are being made and replaced each year.' -- source: https://arstechnica.com/gadgets/2022/11/used-thin-client-pcs-are-an-unsexy-… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Anker's Eufy Cameras Caught Uploading Content To the Cloud Without User Consent
by Peter Reutemann 30 Nov '22

30 Nov '22

'Anker's popular Eufy-branded security cameras appear to be sending some data to the cloud, even when cloud storage is disabled and local only storage settings are turned on. MacRumors reports: The information comes from security consultant Paul Moore, who last week published a video outlining the issue. According to Moore, he purchased a Eufy Doorbell Dual, which was meant to be a device that stored video recording on device. He found that Eufy is uploading thumbnail images of faces and user information to its cloud service when cloud functionality is not enabled. Moore demonstrates the unauthorized cloud uploading by allowing his camera to capture his image and turning off the Eufy HomeBase. The website is still able to access the content through cloud integration, though he had not signed up for cloud service, and it remains accessible even when the footage is removed from the Eufy app. It's important to note that Eufy does not appear to be automatically uploading full streaming video to the cloud, but rather taking captures of the video as thumbnails. The thumbnails are used in the Eufy app to activate streaming video from the Eufy base station, allowing Eufy users to watch their videos when away from home, as well as for sending rich notifications. The problem is the thumbnails are uploaded to the cloud automatically even when the cloud functionality is not active, and Eufy also seems to be using facial recognition on the uploads. Some users have taken issue with the unauthorized cloud uploads because Eufy advertises local-only service and has been popular among those who want a more private camera solution. "No Clouds or Costs," reads the Eufy website. Moore suggests that Eufy is also able to link facial recognition data collected from two separate cameras and two separate apps to users, all without camera owners being aware. Moore received a response from Eufy in which Eufy confirmed that it is uploading event lists and thumbnails to AWS, but said the data is not able to "leak to the public" because the URL is restricted, time limited, and requires account login. There is also another issue that Moore has highlighted, suggesting Eufy camera streams can be watched live using an app like VLC, but little information on the exploit is available at this time. Moore said that unencrypted Eufy camera content can be accessed without authentication, which is alarming for Eufy users. There's a dedicated Reddit thread where other Eufy users are reporting the same thing happening.' -- source: https://yro.slashdot.org/story/22/11/29/2148250 Eufy products are for sale here in NZ as well. Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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