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AI Worming through Word

AI Worming through Word

AI Worming through Word Neat new prompt injection variant by Håkon Måløy, who found a way to upgrade prompt injection attacks against Microsoft Word to full self-replicating worms: An attacker places hidden instructions in a document that is later used as source material in Copilot for Word. Copilot may interpret those instructions as part of the user’s request, causing it to manipulate the document being drafted or edited. Copilot may then also copy the hidden instructions into the resulting…

Simon Willison's Weblog
Quoting Matthew Green

Quoting Matthew Green

Right now we’re in the midst of a historic transition from traditional public-key algorithms based on EC-based cryptography and RSA, moving over to new post-quantum algorithms based on novel problems. This is why there are so many standards like HAWK being considered. If there was ever a perfect time for a massive new public cryptanalysis capability to come on line, we’re in it. So unless AIs succeed in undermining all of our hard problems altogether (or we live in Impagliazzo’s Minicrypt) then…

Simon Willison's Weblog
Discovering cryptographic weaknesses with Claude

Discovering cryptographic weaknesses with Claude

Discovering cryptographic weaknesses with Claude The best part of this article (here's the repo) about how Anthropic researchers used Claude Mythos to find mathematical flaws in both HAWK and a weaker version of AES ("neither of these results has a practical impact on today’s computer systems") is the prompts that they shared, spelling mistakes included: the models tend to think it is impossible to solve so they don't try they need a good amount of prompting. why not do aes-128 r7? the whole…

Simon Willison's Weblog
Quoting Akshat Bubna

Quoting Akshat Bubna

We’re aware a Modal customer published an unauthenticated endpoint that allowed ​anyone on the internet to use ​their ⁠sandboxes for code execution. This was used by the rogue agent. Modal’s ⁠platform ​or isolation were not ​compromised in anyway. — Akshat Bubna, Modal's CTO, talking to Reuters about this incident Tags: ai-security-research, openai, sandboxing, security, openai-hugging-face-incident

Simon Willison's Weblog
uv 0.12.0

uv 0.12.0

uv 0.12.0 Some interesting breaking changes in this release of uv, in particular to the default project produced by the uv init command. uv init is the uv shortcut for creating a new project. The previous version of uv, version 0.11.x, produced this directory when you ran uv init uv-init. Here's what you get with uv 0.12. I have a GitHub repository that automatically snapshots the output of uv init, so you can also see the full diff: uv init now defaults to a src/ shaped package, instead of…

Simon Willison's Weblog
Anatomy of a Frontier Lab Agent Intrusion: A Technical Timeline of the July 2026 Incident

Anatomy of a Frontier Lab Agent Intrusion: A Technical Timeline of the July 2026 Incident

Anatomy of a Frontier Lab Agent Intrusion: A Technical Timeline of the July 2026 Incident Hugging Face just released this extremely detailed technical description of OpenAI's recent accidental cyberattack against their infrastructure. This attack was very sophisticated, and the resulting document doubles as a crash-course in modern adversarial security approaches. We're still waiting for more details from OpenAI on how their agent broke out of its sandbox. The package proxy that it found a…

Simon Willison's Weblog
moonshotai/Kimi-K3

moonshotai/Kimi-K3

moonshotai/Kimi-K3 As promised earlier this month, Moonshot have released the weights for their excellent 2.8 trillion parameter Kimi K3. They're a hefty 1.56TB on Hugging Face. Kimi introduced their own janky modified version of the MIT license with K2 back in July 2025. That license just added this paragraph requiring attribution beyond a certain size of commercial entity: Our only modification part is that, if the Software (or any derivative works thereof) is used for any of your commercial…

Simon Willison's Weblog
An opinionated guide to which AI to use to do stuff

An opinionated guide to which AI to use to do stuff

An opinionated guide to which AI to use to do stuff It's interesting watching the evolution of Ethan Mollick's guide over time. A year ago it was still all about chat - ChatGPT, Claude, Gemini - with o3, Claude 4 Opus, and Gemini 2.5 Pro as the models and Deep Research as a useful alternative mode. Today it's much more about agentic systems - "where the AI is capable of doing the equivalent of many hours of real human work in one go". Gemini has fallen off Ethan's list, since Google still…

Simon Willison's Weblog
An Inside Look at the Relay Market Powering Token Resellers and Fraud

An Inside Look at the Relay Market Powering Token Resellers and Fraud

An Inside Look at the Relay Market Powering Token Resellers and Fraud Fascinating investigation by Matt Lenhard into the market that has grown up around reselling LLM tokens at a discount by pooling API keys from various sources. This looks to be mostly a thing in China. Resellers sell access to an LLM proxy that offers significant discounts on regular API pricing, which they achieve by abusing free trials, proxying through unprotected support bots, or sometimes through stolen credit cards or…

Simon Willison's Weblog
Ruff v0.16.0

Ruff v0.16.0

Ruff v0.16.0 Astral shipped a significant new version of their Ruff Python linting tool a few days ago on July 23rd. I noticed today because my various CI jobs all started failing thanks to new default Ruff checks and my unpinned "ruff" dev dependency. From Brent Westbrook's announcement post: Ruff now enables 413 rules by default, up from 59 in previous versions. Since Ruff's default rule set was last modified in v0.1.0, the number of rules in Ruff has grown from 708 to 968. Many of these…

Simon Willison's Weblog
Quoting Boris Cherny

Quoting Boris Cherny

More than any of these eval scores, what is most exciting to me is something else: Opus 5 is our least prompt injectable model yet. It is a bit buried in the system card, but across PI evals and red teaming, Opus 5 is very hard to prompt inject successfully. — Boris Cherny, here's that System Card section, page 73 Tags: prompt-injection, anthropic, claude, generative-ai, ai, llms, boris-cherny

Simon Willison's Weblog
Introducing Claude Opus 5

Introducing Claude Opus 5

Introducing Claude Opus 5 I've been offline kayaking with sea otters for much of today so I haven't had a chance to put Anthropic's new model Claude Opus 5 through its paces yet. The buzz is positive, and Anthropic's description of it as a "thoughtful and proactive model that comes close to the frontier intelligence of Claude Fable 5 at half the price" sounds promising. It's currently leading the Artificial Analysis leaderboard, in front of even Fable 5. It's priced the same as Opus 4.8, and…

Simon Willison's Weblog
The first known runaway AI agent - or a very bad marketing stunt?

The first known runaway AI agent - or a very bad marketing stunt?

The first known runaway AI agent - or a very bad marketing stunt? Martin Alderson's commentary on the OpenAI accidental cyberattack against Hugging Face includes a couple of details I hadn't considered. First, Hugging Face offers a truly rich target if you're trying to find potential vulnerabilities that require executing arbitrary code: Hugging Face has an enormous attack surface. They have more interfaces than I can count which run untrusted models and code. While they definitely have…

Simon Willison's Weblog