There are some torrrents showing up with .lnkextension (ex: movie.mp3.lnk, tvshow.mkv.lnk…) and automated software (Sonarr, Radarr, Lidarr, qBittorrent RSS Downloader) could pick those torrents (but not import).
These (fake) torrents include a .lnk file that executes a script on your Windows
HOW TO exclude from download on qBittorrent.
-
Go to Options -> Downloads
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Enable “Exclude file names”
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Add patterns:
(one by line)
*.mp4.lnk
*.mp3.lnk
*.mkv.lnk
*.torrent.lnk
Or exclude all together: *.lnk
Example on VirusTotal https://www.virustotal.com/gui/file/e74f64df6ebaf3a1b6e3f42591eb6e87d2ac2828eb5a99fd8d3d82c140137fc9/detection
Not using Windows helps a ton :)
Sonarr will still pick the release and download GBs of malware, and if you don’t notice your download directly is filled with GBs of fake torrents
For those interested, John Hammond did a video a few months ago about
.lnkextension (and other 16 hidden extensions on Windows).He doesn’t go to much and to deep into the subject, but you get a general view how this could be exploitable.
Is that the malware that is undetectable because it runs purely in memory? The name is escaping me
Also make sure you have file extensions enabled in Explorer, it makes it waaay harder for something like this to work.
Nice to know! Thank you!
You gotta love how aggressively they prevent users from seamlessly running executables from the internet, a VERY legitimate common use case, but a desktop shortcut from the internet? Run away!
How is the link file executing malware? Can you put any shell script as the target?
You can put the script itself as the link. Shortcut to: powershell -command “Write-Host ‘Gonna pwn your shit’”
I am pretty sure a link file can open cmd/powershell with parameters to execute commands
Yet another reminder that piracy on Linux is the way because new files don’t have execute permissions by default
On many distros will open with WINE by default, not a big deal, you can just delete
~/.wine. If it does anything
thanks Microsoft for hiding extensions by default!
Microsoft: De nada, amigo! Oh… here’s an ad, btw… and…did you enable Recall already?
or rather: oh silly you were so clumsy that you disabled recall by accident again. let us be so kind to re-enable it for you
Yes, but also whoever set the defaults for the *arr tools. Why would any filename with extra shit past the extensions you’re looking for be considered an acceptable result?
Tack $ on the end of your regex, for fucks sake.
Is not regex
https://github.com/qbittorrent/qBittorrent/pull/17106Examples
*.exe: filter ‘.exe’ file extension.
readme.txt: filter exact file name.
?.txt: filter ‘a.txt’, ‘b.txt’ but not ‘aa.txt’.
readme[0-9].txt: filter ‘readme1.txt’, ‘readme2.txt’ but not ‘readme10.txt’
When I read the title, I was thinking of something sophisticated such as hidden executable streams inside the MKV container (IIRC, it’s possible to append binary data other than audio, video or subtitles specifically inside a MKV). The “.lnk” trick only works in Windows and, even there, it’s easy to prevent: Windows Explorer > Options > Advanced > find and check “Always show extensions for files” (i can’t really remember the exact label for this option as I’m not a Windows user, but something like this will be there).
I believe you uncheck “Hide extensions for known file types”
Exactly! Thanks! I couldn’t point the exact label, I’ve been using Linux for years in a daily basis so I forgot most of the Windows shortcuts/options.
Even then, that setting doesn’t unhide the “.lnk” file extension, that requires a registry edit: https://www.askvg.com/tip-how-to-show-file-extensions-of-shortcuts-lnk-url-pif-in-windows-explorer/
Although shortcuts are pretty easy to spot in the first place unless you just double-click things without paying attention lol
I use Arch btw
What if it executes and install Windows 11 on your machine!?
That would be the very worst malware. I mean both the malware that installed it and win11…
ackshually the proprietary .lnk shortcut format can only be run on windows 🤓
A Linux executable can’t be named ending on .lnk? 🤔🤔
Making such a polyglot that can run on both systems requires much more effort for little gain.
But its not lnk but an executable that needs to be excecuted manually?
Oh lord please have mercy! Blacklisting the file extension right now!
Me too, but don’t want to download GBs of malware and bandwidth
.lnk files are less than 4kb
Not these ones, some could have more than 1GB, look at the virustotal link, the file had 422MB.
Also Sonarr/Radarr filter torrents by size
Here some examples
https://bt4gprx.com/search?q=The.Lord.of.The.Rings.The.Rings.of.Power.S02E08Those where posted on 1337x (and removed) and probably other sites, Sonarr can pick those based on release name and torrent size
PS: had to rename the fine from
.lnkto.comso virustotal could acceptThat would seem suspicious. I’m sure they have some way to pad out the size.
Anyone paying attention to size would probably also notice they’re just .lnk files.
Not necessarily. Even with “hide extensions” unchecked, Windows hides the .lnk extension by default; it just shows an arrow in the bottom-right corner of the icon, which is plausibly missed when in the list view. I’m surprised antivirus doesn’t know about it already tbh.
Weak.
Harbor disaster. Seed the malware. Spread the fruits of chaos amongst the unworthy. Be complicit in their downfall. Feed on their agony ^^/s
Could you just add *.lnk?
That’s mentioned near the bottom of the post.
