Just wrapped up a 30-day enforcement test of all Vision One's attack surface reduction (ASR) rules across our dev and staging environments. Wanted to see what would break before we even considered production.
The initial blast radius was significant. We went from a handful of weekly alerts to several hundred per day. The noise was expected, but the specifics were revealing.
Here's what actually broke our workflows:
* **Build pipelines choked.** Several ASR rules targeting script behaviors blocked legacy PowerShell modules our Jenkins agents still relied on. No graceful failures either—hard crashes.
* **Internal tooling stopped working.** A custom deployment orchestrator written in Python was flagged for "process creation from PSExec and WMI interpreters." Took us two days to refactor it.
* **False positives on admin tasks.** Routine infrastructure commands executed via our management jump boxes were constantly flagged as "suspicious." The volume threatened to drown out real threats.
The key was tuning, not just enabling. We ended up with a three-phase rollout:
1. **Audit Mode for everything** for one week. Just logged, no blocks.
2. **Analyzed the logs** and created exclusion policies for critical business processes. The exclusions are granular (path, hash, certificate) which is good.
3. **Enforced in waves**, grouped by rule risk profile. Started with the "high confidence, low disruption" rules first.
Final tally: Out of the full set of ASR rules, we are now fully enforcing about 65%. Another 20% are in audit-only because the false positive rate is still too high for our comfort. The remaining 15% are disabled—they broke things with no tangible security benefit for our specific stack.
Takeaway: It's a powerful feature set, but turning it all on at once is a recipe for downtime. You need a controlled, monitored rollout with clear rollback plans. The data it provided was invaluable for hardening our systems, but it was a month of careful work, not a flip of a switch.
Build once, deploy everywhere
Great to see someone taking the audit-first approach. That initial blast radius is so common, especially with older automation.
Your point about the build pipelines is key. We had a similar mess with an old SSIS package that spawned cmd.exe in a weird way. It ran fine for years until an ASR rule saw it as "obfuscated script." The audit logs were a lifesaver - we could pinpoint the exact parent process and command line to build an exclusion, instead of just guessing.
The three-phase rollout is smart. Did you find any rules that generated so much noise in audit mode that you decided to just skip enforcement entirely? We had one on office macros that was practically useless for our environment.
The audit log phase is crucial, but man, that first week of logs can be a special kind of hell. We had a rule flagging "executable content from email" that logged every single time Outlook did... anything. The SIEM team threatened to revolt.
Your three-phase plan is solid. We found we had to add a "phase zero" - just turning the rules on in audit for one team's subset of servers first. The volume was still insane, but at least it was contained.
Did you build your exclusions based purely on process path, or did you get into hashing? We went with paths initially for speed, but then had to chase down a bunch of changes when someone updated a tool.
NightOps
Your "phase zero" concept is essential and something we've standardized on. Starting with a single, controlled team gives you a predictable log volume to develop your triage and exclusion processes against. It turns chaos into a manageable procedure.
Regarding your question on exclusions, we started with process paths for initial triage speed, but that's a temporary fix. The maintenance burden is too high. We moved to a hybrid model. For in-house tools, we sign them with an internal certificate and exclude based on the publisher certificate. For third-party tools where we control the deployment, we use file hash exclusions but manage them through our deployment system - the hash is captured at release and the ASR policy is updated automatically. For everything else, like updated vendor installers, we use path exclusions but with a strict wildcard pattern, like `C:Program FilesVendorAppbin*.exe`, which balances stability with some control.
The "executable content from email" rule is notoriously noisy. We found its value was near zero for our standard workstations but critical for a subset of high-risk users. We ended up splitting the policy: a baseline with that rule off for most, and a strict policy with it on for finance and executive assistants.