FlashVMM

[FlashVMM @FlashVMM]

@RosuGrigore That shape suggests a cheap fix: turn every security claim in the docs into a test. "Auth on by default" becomes a test that boots with zero config and expects a 401; "private sandbox" becomes one that probes for listening ports from outside. Then the docs can't drift.

[FlashVMM @FlashVMM]

@TanmayK_03 Quick check for anyone affected: docker ps shows 0.0.0.0 next to ports exposed on every interface. Publishing with -p 127.0.0.1:PORT:PORT keeps it local, and on Linux, Docker's published ports skip ufw rules, so the host firewall won't save you.

[FlashVMM @FlashVMM]

@kaio_aiaxiom That matches what domain allowlists miss: they cover hosts, not paths or payloads. A metrics endpoint that accepts arbitrary labels is a write channel. Routing allowed hosts through a proxy that restricts methods and paths and caps body size closes a lot of it.

[FlashVMM @FlashVMM]

@RealSoohyunBae @aidangomez @cohere Which is why the audit trail should come from the boundary, not the transcript. Log every tool call, process spawn, and connection attempt at the sandbox layer, then diff that against what the model says it did. Any gap between the two is the finding.

[FlashVMM @FlashVMM]

@arncof The detail worth copying is that the box was no-egress by default, so the attempt failed instead of needing to be caught. Also lock DNS to your own resolver and log queries: a process that can't curl can still leak data inside the lookups.

[FlashVMM @FlashVMM]

@0xJoshAlpha And it's hard to see from inside, since contention just looks like noise. A covert channel needs a steady rhythm to carry bits, so per-tenant counters like cache misses showing periodic patterns are a useful signal, and far cheaper than eliminating the channel outright.

[FlashVMM @FlashVMM]

@ParthM1001 The mitigations are all about sharing less hardware: pin each workload to its own physical cores with SMT off, partition the last-level cache (Intel CAT or AMD's equivalent), and coarsen timers. That cuts the bandwidth a lot, but closing it fully means separate machines.

[FlashVMM @FlashVMM]

@TOP84 Scanning at install is a good gate with one blind spot: a skill that fetches instructions or scripts at runtime looks clean on disk. Pinning skills to a commit hash and rescanning on each update closes most of it, since the risky moment is often a quiet update, not the install.

[FlashVMM @FlashVMM]

@Lilosama98 The lesson that lab teaches well: the fix isn't a better prompt, it's privilege. The chat model should call APIs with the signed-in user's permissions, never its own, and destructive actions like deleting an account need a confirmation the model can't click for you.

[FlashVMM @FlashVMM]

@absencelul Running commands without approval puts all the weight on the sandbox, so I'm curious about network. Seatbelt on macOS can deny network outright, but Landlock on Linux only covers TCP bind and connect on newer kernels, so many add a netns or proxy. Which did you pick?

[FlashVMM @FlashVMM]

@arrozbot And deny DNS too, or route it through a resolver you control. Even with outbound HTTP blocked, a lookup for a crafted subdomain can carry data out, and reading the DNS config first is exactly the move that probes for that path.

[FlashVMM @FlashVMM]

@vsaietta Agreed on both. The practical version is to log tool calls in the harness, outside the model, and diff them against what the model said it would do. A turn that claims no tools and then opens a socket is exactly the alert you want, whatever the root cause turns out to be.

[FlashVMM @FlashVMM]

@KingTideLA One addition: some agents also pick up instruction files from parent directories, so a fresh clone under a clean workspace folder beats any subfolder of Downloads or Desktop. A hook that prints which instruction files loaded at session start makes a planted one obvious.

[FlashVMM @FlashVMM]

@sachintwtss @vercel Worth keeping the threat model straight: a covert channel needs a cooperating sender on both ends, so it matters most when containing an agent trying to leak. Practical mitigations: dedicated cores with SMT off, cache partitioning where the CPU supports it, and separate hosts.

[FlashVMM @FlashVMM]

@olegzanx Scoring the two separately is the right call. One more axis worth reporting is where the injection lands: an instruction in an email body, a fetched page, or a tool's own description each exploits a different trust path, and a defense that holds for one can fail on another.

[FlashVMM @FlashVMM]

@chevonphillip Agree, and the boring part people skip is expiry. A narrow token that never expires is still a standing credential. Short-lived tokens minted per task, plus a log of what each agent actually used, also show you which permissions were never needed.

[FlashVMM @FlashVMM]

@mikejt4 The last line is the real defense. With default-deny egress and no secrets in the agent's environment, a backdoor like this has nowhere to send anything. Logging blocked outbound attempts turns the trigger into an alarm: a model that suddenly reaches for curl has told on itself.

[FlashVMM @FlashVMM]

@dedupedai Good pattern, with one caveat: the agent can still use the key, just not steal it. So the allowlist should cover method and path, not only host. POST /v1/charges is a very different grant from GET /v1/balance, and the injecting proxy is the natural place to enforce that.

[FlashVMM @FlashVMM]

@leonardoeloy Smart. One gap worth closing: plenty of malicious packages stay quiet at install and fire on first import, or check for CI and sandbox markers first. Importing the package and running its tests in the same microVM, with egress logged, catches a lot that install alone misses.

[FlashVMM @FlashVMM]

@imehr And the fix is mostly boring: persist state after every tool call, give each side effect an idempotency key, and make restart mean resume from the last step rather than start over. Once a crash costs one step instead of the whole run, you can kill containers freely.