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
-
Enable “Exclude file names”
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Add patterns:
(one by line)
*.mp4.lnk
*.mp3.lnk
*.mkv.lnk
*.torrent.lnk
*.zipx
*.scr
*.arj
*.lzh
Or exclude all together: *.lnk
Example on VirusTotal https://www.virustotal.com/gui/file/e74f64df6ebaf3a1b6e3f42591eb6e87d2ac2828eb5a99fd8d3d82c140137fc9/detection
Also make sure you have file extensions enabled in Explorer, it makes it waaay harder for something like this to work.
Nice one OP. Just had sonar pick up one of these today named like a proper release of a trusted group. Sonarr didn’t move it from qbit but better to not DL it in the first place even though its a linux box
that executes a script on your Windows.
I don’t have a Windows.
Then just draw on your wall.
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Probably this will help as well at the arr end: https://forums.sonarr.tv/t/automatic-blacklist-malware/37822
Nice to know! Thank you!
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
We just deleted those failed to import periodically with an automation 😁
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 or 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
Could you just add *.lnk?
That’s mentioned near the bottom of the post.
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Ah yes you’re right
What did they say?
The elephant is the only animal with 4 knees.
Probably that OP mentioned that.
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.
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I use Arch btw
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
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!
thanks Microsoft for hiding extensions by default!
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’
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
Have you tried setting your region to Europe? it’s not an issue here
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 anythingWine will mount your root folder as a Windows drive by default. So if the malware is scanning all connected drives and encrypting/uploading them you still have a problem.
How is the link file executing malware? Can you put any shell script as the target?
I am pretty sure a link file can open cmd/powershell with parameters to execute commands
yep! I’ve found out browsing hacking/spamming site and i’ve found something too good to be true, it downloaded archive nested inside other archive and in it was silngle .lnk file leading to “the resource”. Peeking inside i’ve found powershell executing base64 (or base32?) encoded script (it’s got commandline option for that. if you want to ask wtf ask microsoft, and tell me), it dl’d some exe from some site and ran it, site was down alredy.
You can put the script itself as the link. Shortcut to: powershell -command “Write-Host ‘Gonna pwn your shit’”
