72 comments

  • drewgregory 3 hours ago

    I am very passionate about this question - so much so that I happened make a blog post about it yesterday!

    I recommend giving LLMs credentials that are extremely fine-grained, where the credentials can only permit the actions you want to allow and not permit the actions you don't want to allow.

    Often, it may be hard or impossible to do this with your database settings alone - in that case, you can use proxies to separate the credentials the LLM/agent has from the credentials that are actually made to the DB. The proxy can then enforce what you want to allow or block.

    SSH is trickier because commands are mixed in with all the other data going on in the bytestream during your session. I previously wrote another blog post about just how tricky enforcing command allowlists can be as well: https://www.joinformal.com/blog/allowlisting-some-bash-comma.... A lot of developer CLI tools were not designed to be run by potentially malicious users who can add arbitrary flags!

    I also have really appreciated simonw's writing on the topic.

    Disclaimer: I work at Formal, a company that helps organizations use proxies for least privilege.

    • SOLAR_FIELDS 3 hours ago

      Your post can be succinctly formalized as “there should always be a deterministic validation layer sitting between the agent and anything sensitive it could do”

      • mikestorrent 2 hours ago

        Is true for interns, should be true for LLMs. There should simply be no way for it to get keys for prod.

    • DennisAleynikov 3 hours ago

      Thanks for making this blog post, very informative!

      I've found as well that while you can run agents with a lot of tools and set them free autonomously they tend not to be prompted correctly by default to not get enormously stuck and do really dumb things along the way.

      Never open pandoras box without understanding the implications and principle of least privilege and trust apply at every layer of the equation now

  • fhub 3 hours ago

    Our solve is to allow it to work with a local dev database and it's output is a script. Then that script gets checked into version control (auditable and reviewed). Then that script can be run against production. Slower iteration but worth the tradeoff for us.

    Giving LLM even read access to PII is a big "no" in my book.

    On PII, if you need LLMs to work on production extracted data then https://github.com/microsoft/presidio is a pretty good tool to redact PII. Still needs a bit of an audit but as a first pass does a terrific job.

    • Volundr 2 hours ago

      This. Everything your LLM reads from your database, server, whatever is being sent to your LLM provider. Unless your LLM is local running on your own systems, it shouldn't be given ANY access to production data without vetting it through legal with an eye to your privacy policy and compliance requirements.

    • maxkfranz 2 hours ago

      The script method is great, and it's generalisable to things outside of DB access.

      E.g. I used this method when I wanted to carry out a large (almost every source file) refactoring of Cytoscape.js. I fed the LLM a bunch of examples, and I told it to write a script to carry out the refactoring (largely using regex). I reviewed the script, ran the script, and then the code base was refactored.

      At the time, agents were not capable enough of doing large-scale refactors directly, as far as I was aware. And the script was probably much faster, anyway.

    • hephaes7us 2 hours ago

      Agreed - I run an entire second dev environment for LLMs.

      Claude code runs in a container, and I just connect that container to the right network.

      It's nice to be able to keep mid-task state in that environment without stepping on my own toes. It's easy to control what data is accessible in there, even if I have to work with real data in my dev environment.

  • jedberg an hour ago

    Use tool calling. Create a simple tool that can do the calls that are allowed/the queries that are allowed. Then teach the LLM what the tools can do. Allow it to call the tool without human input.

    Then it will only stop when it wants to do something the tool can't do. You can then either add that capability to the tool, or allow that one time action.

  • JoshTriplett 4 hours ago

    Don't.

    Among the many other reasons why you shouldn't do this, there are regularly reported cases of AIs working around these types of restrictions using the tools they have to substitute for the tools they don't.

    Don't be the next headline about AI deleting your database.

    • ninju 3 hours ago
    • codingdave 2 hours ago

      You need to secure the account an LLM-based app runs under, just like you would any user, AI or not. When you hire real people, do you grant them full privileges on all systems and just ask them not to touch things they shouldn't? No, you secure their accounts to the specific privileges they need, and no more. Do the same with AI.

    • nico 4 hours ago

      > Don't

      Do you mean "Don't give it more autonomy", or "Don't use it to access servers/dbs" ?

      I definitely want to be cautious, but I don't think I can go back to doing everything manually either

      • bigstrat2003 2 hours ago

        You have to choose between laziness or having systems that the LLM can't screw up. You can't have both.

      • hephaes7us 2 hours ago

        You can have it write code that you review (with whatever level of caution you wish) and then run that on real data/infrastructure.

        You get a lot of leverage that way, but it's still better than letting AI use your keys and act with full autonomy on stuff of consequence.

      • dsr_ 3 hours ago

        Why aren't you using the tools we already have: ansible, salt, chef, puppet, bcfg2, cfengine... every one of which was designed to do systems administration at scale.

        • dpoloncsak 3 hours ago

          "Why would you use a new tool when other tools already exist?".

          Agents are here. Maybe a fad, maybe a mainstay. Doesn't hurt to play around with them and understand where you can (and can't) use them

      • JoshTriplett 3 hours ago

        I mean, both, but in this case I'm saying "don't use it to access any kind of production resource", with a side order of "don't rely on simple sandboxing (e.g. command patterns) to prevent things like database deletions".

  • nl 10 minutes ago

    I wrote my own agent where everything happens over SSH.

    The shell is SSH, the read_file and write_file tool calls are over SSH

    Then I give it a disposable VM and let it go.

    There are lots of other solutions, but it's an interesting problem to work on.

  • simonw 4 hours ago

    For database stuff most databases like PostgreSQL have robust permissions mechanisms built in.

    No need to mess around with regular expressions against SQL queries when you can instead give the agent a PostgreSQL user account that's only allowed read access to specific tables.

    • nico 4 hours ago

      You are right, and that's great for queries

      How do you provide db access? For example, to access an RDS db, you have to connect from within the AWS/EC2 environment, which means either providing the agent ssh access to a server, from which it can run psql, or creating a tunnel

      Additionally, with multiple apps/dbs, that means having to do the setup multiple times. It would be nice to be able to only configure the agent instead of all the apps/dbs/servers

      • tracker1 4 hours ago

        You can't provide an existing ssh tunnel with a port for said database yourself, locally?

      • browningstreet 4 hours ago

        "aws iam service accounts"

  • helsinki 11 minutes ago

    Jump host with restricted commands / access. Agents SSH into a jump host and execute what they are allowed to execute.

  • PaulHoule 4 hours ago

    See https://simonwillison.net/2025/Feb/3/a-computer-can-never-be...

    I'll set it loose on a development or staging system but wouldn't let it around a production system.

    Don't forget your backups. There was that time I was doing an upgrade of the library management system at my Uni and I was sitting at the sysadmin's computer and did a DROP DATABASE against the wrong db which instantly brought down the production system -- she took down a binder from the shelf behind me that had the restore procedures written down and we had it back up in 30 seconds!

  • dormento 4 hours ago

    > Safely

    You cannot. The best you can ever hope for is creating VM environments, and even then it's going to surprise you sometimes. See https://gtfobins.github.io/.

  • zachmu 3 hours ago

    We build DoltDB, which is a version-controlled SQL database. Recently we've been working with customers doing exactly this, giving an AI agent access to their database. You give the agent its own branch / clone of the prod DB to work on, then merge their changes back to main after review if everything looks good. This requires running Dolt / Doltgres as your database server instead of MySQL / Postgres, of course. But it's free and open source, give it a shot.

    https://github.com/dolthub/dolt

  • cortesoft 3 hours ago

    For DB access, use an account with the correct access level you want to grant.

    For SSH, you can either use a specific account created for the AI, and limit it's access to what you want it to do, although that is a bit trickier than DB limits. You can also use something like ForceCommand in SSHD config (or command= in your authorized_keys file) to only grant access to a single command (which could be a wrapper around the commands you want it to be able to access).

    This does somewhat limit the flexibility of what the AI can deal with.

    My actual suggestion is to change the model you are using to control your servers. Ideally, you shouldn't be SSHing to servers to do things; you should be controlling your servers via some automation system, and you can just have your AI modify the automation system. You can then verify the changes it is making before committing the changes to your control system. Logs should be collected in a place that can be queried without giving access to the system (Claude is great at creating queries in something like ElasticSearch or OpenSearch).

  • benreesman 25 minutes ago
  • arjie 2 hours ago

    For the database, I use a read-only user. I also give it full R/W to a staging DB and the local dev DB. Even if it egresses that, nothing can happen.

    SSH I just let it roll because it's my personal stuff. Both Claude and Codex will perform unholy modifications to your environment so I do the one bare thing of making `sudo` password-protected.

    For the production stuff I use, you can create an appropriate read-only role. I occasionally let it use my role but it inevitably decides to live-create resources like `kubectl create pod << YAML` which I never want. It's fine because they'll still try and fail and prompt me.

    • fhub 2 hours ago

      Are you comfortable giving LLM read access to fields that have PII? Anything related to authentication? Is it allow-list of access or a deny-list?

      • arjie 2 hours ago

        I am comfortable with that in dev/staging DB (it's my own PII which I don't mind). I use separate secrets for staging vs. prod so I don't mind giving full bore access to staging.

        For prod DB read-only I just add tables/columns as they become relevant (so it's allowlist). Claude usually sequences table schema and stuff from staging DB / local migrations and then reads prod DB. When it fails access to something I decide if I want to give it or not. It eventually reaches a stage where I'm comfortable with always starting my day with `claude --dangerously-skip-permissions --continue`.

        The prod DB read/write creds are in company 1password which I don't have app installed (I rarely need company creds). LLM maybe could figure out some way to get into my Bitwarden which I do routinely use but short of creating and running keylogger I think it's fine.

        It's mildly annoying you have to periodically `GRANT SELECT` but now I'm much more careful organizing the schema in an LLM-friendly way. Postgresql can do column-security and I'm forced to use that sometimes but I refactored design to just be table-level.

  • frio 2 hours ago

    I do wonder if LLMs will see tools like immudb (https://immudb.io/) or Datomic (https://www.datomic.com/) receive a bit more attention. The capacity to easily rollback the state to a previous immutably preserved state has always seemed like a fantastic addition to databases to me, but in the era of LLMs, even more important.

  • almosthere 5 minutes ago

    have it only write python code and run it, disallow it to ever delete or update data in a database.

  • Terr_ 5 hours ago

    I imagine your best bet are exactly the same tools for a potentially-malicious human user: Separate user account, file permissions, database user permissions, etc.

    • nico 4 hours ago

      This is probably the safest thing to do, also the most time consuming

      It would be nice to just be able to solve it through instructions to the agent, instead of having to apply all the other things for each application/server/database that I'd like to give it access to

      • wrs 4 hours ago

        That would be nice. If only the agent had the ability to limit itself to your instructions.

      • cvhc 3 hours ago

        The restrictions have to be enforced by the non-LLM deterministic control logics (in the OS/database/software, or the agent's control plane). It cannot be just verbal instructions and you expect the LLM not to generate certain sequences of tokens.

        What I imagine is you might instruct an agent to help you set up the restrictions for various systems to reduce the toil. But you should still review what the agent is going to do and make sure nothing stupid is done (like: using regexes to filter out restricted commands).

      • ljm 4 hours ago

        Yeah but this is like exposing `sudo eval $input` as a web service and asking the clients to please, please, not do anything bad.

        Can create scripts or use stuff like Nix, Terraform, Ansible or whatever to automate the provisioning of restricted read only accounts for your servers and DBs.

      • maxbond 3 hours ago

        That's equivalent to client-side security.

  • tobyhinloopen an hour ago

    A great start is to have LLMs use special UNIX users that can’t do anything except that you allowed them to do, including accessing the database with a read only user.

  • cadamsdotcom 3 hours ago

    Appropriate fine grained permissions, or a readonly copy.

    This is nothing new; it’s the logical thing for any use case which doesn’t need to write.

    If there is data to write, convert it to a script and put it through code review, make sure you have a rollback plan, then either get a human or non-AI automation tooling to run it while under supervision/monitoring.

    Again nothing new, it’s a sensible way to do any one-off data modification.

    • fhub 2 hours ago

      What is new to me is that people let LLMs consume PII and potentially authentication related data. This, frankly, is scary to me.

  • throwaway140126 2 hours ago

    I just want to share my thoughts about this topic:

    Personally I think the right approach is to treat the llm like a user.

    So if we pretend that you would like to grant a user access to your database then a reasonable approach would be to write a parser (parsing > validating) to parse the sql commands.

    You should define the parser such that it only uses a subset of sql which you consider to be safe.

    Now if your parser is able to parse the command of the llm (and therefore the command is part of the subset of sql which you consider to be safe) then you execute the command.

  • e12e 3 hours ago

    For ssh/shell - set up a regular user, and add capabilities via group membership and/or doas (or sudo).

    You want to limit access to files (eg: regular user can't read /etc/shadow or write to /bin/doas or /bin/sh) - and maybe limit some commands (/bin/su).

  • Curzel 4 hours ago

    For db just give it credentials of a readonly user, for instructions you can do this. You can give setup a list of approved tools and bash commands https://www.anthropic.com/engineering/claude-code-best-pract...

    • fhub 2 hours ago

      Do you let it consume PII? Anything related to authenticaion?

      • ziml77 7 minutes ago

        Not everyone is handling PII. Where I work, anything like that is only available to a very limited set of people who absolutely need to be able to see it. Also some systems allow access control at the column and even row level, so even if it's intermingled with other data you want the LLM to read, you might be able to mask it that way.

        Also, people shouldn't be running any LLM on data of a business without a proper contract in place like you have with any vendor who has access to your data. And if there's specific PII requirements, those should be covered too.

  • stephendause 5 hours ago

    There is an example of [dis]allowing certain bash commands here: https://code.claude.com/docs/en/settings

    As for queries, you might be able to achieve the same thing with usage of command-line tools if it's a `sqlite` database (I am not sure about other SQL DBs). If you want even more control than the settings.json allows, you can use the claude code SDK.

    • nico 5 hours ago

      Great pointers, thank you

      How would you go about allowing something like `ssh user@server "ls somefolder/"` but disallowing `ssh user@server "rm"`?

      Similarly, allow `ssh user@server "mysql \"SELECT...\""`, but block `ssh user@server "mysql \"[UPDATE|DELETE|DROP|TRUNCATE|INSERT]...\""` ?

      Ideally in a way that it can provide more autonomy for the agent, so that I need to review fewer commands

      • ktm5j 4 hours ago

        Sounds like this might help: https://www.gnu.org/software/bash/manual/html_node/The-Restr...

        I'm not familiar with rbash, but it seems like it can do (at least some of) what you want.

      • onmai-xyz 4 hours ago

        If you control the ssh server it can be configured to only allow what you want. Certainly tedious but I would consider it worth while as it stands with agents being well, agentic.

      • stephendause 4 hours ago

        I don't know; I've never done something like that. If no one else answers, you can always ask Claude itself (or another chatbot). This kind of thing seems tricky to get right, so be careful!

        • nico 4 hours ago

          Yup definitely tricky. Unfortunately Claude sucks at answering questions about itself, I've usually had better luck with ChatGPT. Will see how it goes

  • al_borland 3 hours ago

    You could setup permissions on the user Claude is using to only be able to run those commands. But that may be easier said than done, depending on the size of your environment and the management tools you have.

  • christophilus 5 hours ago

    I run my agents in containers, and only put stuff in those containers that I'm happy obliterating.

    • nico 4 hours ago

      Do you use Claude Code? Do you say "Yes, and don't ask again" for all the commands, since you don't mind breaking things inside the container?

      • NitpickLawyer 4 hours ago

        > claude --dangerously-skip-permissions

        But do not run this on prod servers! You cannot prompt your way into the agent not doing something stupid from time to time.

        Also blacklisting commands doesn't work (they'll try different approaches until something works).

  • vindex10 4 hours ago

    for files, possibly sshfs / fuse with readonly mount

    https://stackoverflow.com/questions/35830509/sshfs-linux-how...

  • j45 an hour ago

    Asking non-deterministic software to only behave like deterministic software in certain case magically is the thing to reflect on.

    If we want it to be 100% safe, you probably don't ever do it with non-deterministic layers alone.

    - Creating tools and tool calling helps

    - Claude code specifically asks permissions to run certain commands in certain folders and keeps a list of that. Chances are that is an actual hard filter locally when the llm recommends a command.

    This would be creating a deterministic layer to keep the non-deterministic layer honest. This is mandatory because ai models don't return the same level of smarts and intelligence all the time.

    - Another step that can help is layering the incoming request and the command sent to the CLI between more layers and checks and no direct links to dilute any prompt injection, etc.

  • rcarmo 3 hours ago

    I build MCP servers that limit the LLM to specific commands.

  • smashah an hour ago

    I think this is a good opportunity for a tool like warpgate. It has an API to create unique ssh sessions for one time use.

    I've just rolled an instance but it's quite powerful in terms of control. I imagine it would be fairly simple to implement an MCP user group which is barred from using some commands. If a barred command is run the session disconnects.

  • bigstrat2003 2 hours ago

    You don't.

  • hiccuphippo 3 hours ago

    Give them a read-only account.

  • singleshot_ 2 hours ago

    > OK: ls, grep, cat, tail

    cat /dev/random > /dev/sda

    Uh oh…

  • QuadmasterXLII 3 hours ago

    Tell claude that you have to manually review every single command, and this is very expensive. It will pivot to techniques that achieve tasks with many fewer commands / lines of code. Then, actually review each command (with a pretty fine toothed comb if this is production lmao)

  • gunalx 4 hours ago

    Never gibe perms to begin with. Anything the chatbot has access to fuckup it eventually will. So the problem is inherently flawed, but.

    Use db permissions with read only, and possibly only a set of prepared statements. Give it a useraccount with read-only acces maybe

  • jrflowers 3 hours ago

    Only give LLMs SSH access to a machine that you wouldn’t mind getting randomly thrown into the ocean at any moment. Easy peasy

  • einpoklum 3 hours ago

    This is not possible, because systems like "Claude Code" are inherently and fundamentally insecure. Only for models which are open source and with some serious auditing, does the possibility of security even appear.

    Also, about those specific commands:

    * `cat` can overwrite files. * `SELECT INTO` writes new data.

  • TZubiri 2 hours ago

    in posix compatible systems (linux)

    adduser llm su llm

    There you go. Now you can run commands quite safely. Add or remove permissions with chmod chown and chgrp as needed.

    If you need more sophisticated controls try extensions like acl or selinux.

    In windows use its builtin use, roles and file permission system.

    Nothing new here, we have been treating programs as users for decades now.

  • camboo 3 hours ago

    Tl;dr you don’t give your llm ssh access. You give it tools that have individual access to particular executions.

    —-

    Yes, easily. This isn’t a problem when using a proxy system with built in safeguards and guardrails.

    ‘An interface for your agents.’

    Or, simply, if you have a list of available tools the agent has access to.

    Tool not present? Will never execute.

    Tool present? Will reason when to use it based on tool instructions.

    It’s exceptionally easy to create an agent with access to limited tools.

    Lots of advice in this thread, did we forget that ithe age of AI, anything is possible?

    Have you taken a look at tools such as Xano?

    Your agent will only execute whichever tool you give it access to. Chain of command is factored in.

    This is akin to architecting for the Rule of Two, and similarly is the concept of Domain Trusts (fancy way of saying scopes and permissions).