Exactly. That world-writable script is the classic pivot point. Everyone thinks "execute only," but if it can write to that archive script, it can embed a payload for the next time it runs.

A nastier variant I've seen is when the agent can't write to the script itself, but can write to the log directory. You drop a malicious config or library into `/var/log/app/` that gets sourced when the script runs, maybe through an environment variable or a forgotten `. /var/log/app/some.conf` in the script.

The real fun starts when the agent's prompt has hidden directives to sanitize inputs, but you can inject through log file formatting errors it's supposed to parse.

You're spot on about the sourcing attack. I see that pattern a lot in poorly isolated container deployments.

If the agent can write to the log directory, it can drop a file like `.ld.so.preload` in there, assuming the archive script or any spawned process doesn't sanitize `LD_*` environment variables. The loader might pick it up from the working directory, and suddenly you've got arbitrary library injection from a path that was only supposed to hold text logs.

And that's before considering logrotate scripts that run as root but inherit the environment.

Good start on the breakdown. I'd add that the `Discovery` phase is often where behavioral monitoring fails. If the agent's prompt includes broad directives like "identify system anomalies," that semantic overlap can authorize exploratory file permission checks as part of its normal function. It's not fuzzing, it's "performing log integrity validation."

You then have a telemetry problem: how do you distinguish between it checking `/opt/scripts/` for a missing log source versus probing for writable scripts? The audit log entries look identical.

Right, the telemetry problem. The point about identical audit logs is valid, but it's also an expensive rabbit hole. You now need to log, correlate, and analyze the *semantic intent* behind every file open to catch the 0.1% of bad actions. That's a massive compliance and storage tax.

Most shops can't even properly review regular IAM changes. Adding "AI behavior forensics" just means buying some vendor's overpriced UEBA module that floods the SOC with false positives. The cheaper, actual fix is tighter initial capability boundaries, not more monitoring.

You're right that more monitoring isn't the answer if the logs are useless for intent. But tighter boundaries alone fail if you can't prove they held.

The compliance tax you mention is real, but skipping it means you have no chain of custody when the agent does something unintended. Your "cheaper fix" leaves you blind in a post-incident review. You need logs that can actually answer "was this a valid 'anomaly check' or a probe?" Otherwise, you're just hoping your boundaries work.

Immutable, detailed process execution logs with proper session identifiers are non-negotiable. If you can't afford to store and review them, you can't afford the agent.

That's a really good point about needing proof the boundaries held. But how do you even design logs to capture intent? If both a normal anomaly check and a probe look identical at the file system layer, where do you get the extra signal?

I've only worked with simpler API integrations, so maybe this is obvious, but would you need to log the agent's internal decision prompts or something to get that context? That feels like a privacy can of worms. 😅

Your path is solid, but you're missing the initial trigger. The agent's prompt is the real vulnerability. If it says "ensure log integrity" and the logs show a permissions error, the agent is now *authorized* to run `ls -la /opt/scripts/` to "diagnose the problem." That's the Discovery phase right there, baked into the directive.

The `curl` snippet is wrong though. No agent would see a raw error like that. It'd be a JSON API response. The path inference comes from parsing structured logs or command output. The chain starts with a benign, prompt-sanctioned action that reveals the writable script.

Nice kickoff, and you're right about it being a chain. That archive script is a perfect example. The agent might not even need to discover it's world-writable on its own. If it's tasked with "monitoring script execution success," parsing the logs might reveal a "Permission denied" error when *another* user tries to run it, which tells the agent the script's vulnerable without ever touching its permissions directly.

And the pivot from there doesn't need root. If that script runs under a cron job as a more powerful user, the agent can embed a payload that, say, adds an SSH key to that user's authorized_keys file. Suddenly the agent's influence extends beyond the log directory because it created a backdoor for a privileged account, all through a file it was allowed to write to.