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Document-borne AI worms can self-propagate through Copilot for Word

https://enklypesalt.com/posts/context-collapse-part3-ai-worming-through-word/
46•Canopy9560•47m ago

Comments

Canopy9560•46m ago
Author here.

This post covers a coordinated disclosure with Microsoft (MSRC) regarding a vulnerability class that allows attacker-controlled instructions in an attached document to hijack Copilot for Word.

It manipulates the AI to alter the output text (e.g., halving financial figures) and append the attack prompt into the new document concealed as white text.

Because the downstream document now carries the payload, it acts similarly to an AI worm across normal user workflows. Microsoft deployed multiple fixes over a 144-day coordination period, but the broader vulnerability class remains unmitigated and exploitable because it exploits fundamental limitations of current LLMs.

When attacker instructions are combined with legitimate information the model's context window, the tokens being inspected participate in the act of inspection, meaning current LLM architectures provide no reliable boundary between intention and interpretation.

anon48293•34m ago
“ At the time of publication, no robust mitigation for the broader vulnerability class is available.”

Well, that sounds promising..

simonw•30m ago
> Malicious instructions hidden in an externally shared document could make Copilot alter drafted or edited documents in Word and propagate the attack to new documents.

Oh no.

fxwin•23m ago
something something lethal trifecta
baq•7m ago
waiting for W^X reinvented, renamed and marketed for the Agentic Era (r)TM
fg137•8m ago
Mixing instructions and data is never a good idea.

And I thought people understood that.

skybrian•21m ago
Why is it possible to have hidden text in a Word document? Why should the AI have access to that text?
doublerabbit•17m ago
The same reason to why you let AI have access to your filesystem. Idiocy, you need to teach AI to be smart somehow.

You train a monkey to learn from a bunch of level intelligence monkeys. The same applies for AI. Just this time we are the monkeys.

yoz-y•17m ago
It’s the good old white text on white background. Not really a way to defend against this, except having a no-style or high contrast mode that people actually use. Maybe some warning that would trigger if text is too small, off page or has very low contrast would help?
skywhopper•14m ago
The LLM is reading the bytes of the file, not looking at a picture of its rendering. File metadata exists as well, and change history. Tons of places to hide text.

Even if you processed it via a screenshot, image files are processed byte by byte as well and can contain textual metadata.

Ekaros•11m ago
Headers, footers, notes, comments, alt text, probably dozen of other features. Documents often are lot more than just markdown so properly to support everything you do have a lot of ways to hide text for various use cases.
quietbritishjim
teodosin•16m ago
I may be naive here but can the hidden text not be flagged or outright removed before being passed to copilot? Why would there not be consideration for what a human user can see, especially if the hidden text was added by copilot in the first place?
woadwarrior01•15m ago
Could this possible be the first AI worm? Or are there any priors to this?
Canopy9560•5m ago
Morris II(https://arxiv.org/abs/2403.02817) did demonstrate worming behaviour, so the concept at least is not new. However, I do not know of any similar demonstration in a commercial productivity product like Word.
nticompass•14m ago
It's VBScript/macro worms all over again!
ghlancet•12m ago
I mean all your data is already exfiltrated to Copilot, so a little extra worm cannot hurt.

It is fun to see how all AI narratives are collapsing.

RaSoJo•11m ago
Oh but for an alternative to Excel

Purged I would have

All things Microsoft from my (controllable) world

idiotsecant•5m ago
LLMs should be viewed with the same terror as a reckless toddler who knows some bash syntax. Deeply embedding them into important and privileged systems will be the end of us.
•
4m ago
Because, in the 1990s, you would print out your document before giving it to someone else to read. In those times, sometimes you'd want to include text in the document that shows while you're editing it (e.g. notes to yourself or draft text you might want to refer to later) but not when printed.

I believe you would see hidden text by default (but this was a long time ago and I may have misremembered) when in "normal mode" (later "draft mode" and now removed entirely). But when you switch to "print layout mode" (now the usual view unless you're in reading mode) it would be hidden, so you could see what it would be like printed, unless you explicitly turned on the display of hidden text in that mode.

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