80 lines
2.9 KiB
Markdown
80 lines
2.9 KiB
Markdown
# Baseline Policy Example (`baseline.stella`)
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This sample policy provides a balanced default for production workloads: block critical findings, require strong VEX justifications to suppress advisories, and warn on deprecated runtimes. Use it as a starting point for tenants that want guardrails without excessive noise.
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```dsl
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policy "Baseline Production Policy" syntax "stella-dsl@1" {
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metadata {
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description = "Block critical, escalate high, enforce VEX justifications."
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tags = ["baseline","production"]
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}
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profile severity {
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map vendor_weight {
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source "GHSA" => +0.5
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source "OSV" => +0.0
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source "VendorX" => -0.2
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}
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env exposure_adjustments {
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if env.exposure == "internet" then +0.5
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if env.runtime == "legacy" then +0.3
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}
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}
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rule block_critical priority 5 {
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when severity.normalized >= "Critical"
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then status := "blocked"
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because "Critical severity must be remediated before deploy."
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}
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rule escalate_high_internet {
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when severity.normalized == "High"
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and env.exposure == "internet"
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then escalate to severity_band("Critical")
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because "High severity on internet-exposed asset escalates to critical."
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}
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rule require_vex_justification {
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when vex.any(status in ["not_affected","fixed"])
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and vex.justification in ["component_not_present","vulnerable_code_not_present"]
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then status := vex.status
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annotate winning_statement := vex.latest().statementId
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because "Respect strong vendor VEX claims."
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}
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rule alert_warn_eol_runtime priority 1 {
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when severity.normalized <= "Medium"
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and sbom.has_tag("runtime:eol")
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then warn message "Runtime marked as EOL; upgrade recommended."
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because "Deprecated runtime should be upgraded."
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}
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}
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```
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## Commentary
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- **Severity profile** tightens vendor weights and applies exposure modifiers so internet-facing/high severity pairs escalate automatically.
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- **VEX rule** only honours strong justifications, preventing weaker claims from hiding issues.
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- **Warnings first** – The `alert_warn_eol_runtime` rule name ensures it sorts before the require-VEX rule, keeping alerts visible without flipping to `RequiresVex`.
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- Works well as shared `tenant-global` baseline; use tenant overrides for stricter tolerant environments.
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## Try it out
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```bash
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stella policy new --policy-id P-baseline --template blank --open
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stella policy lint examples/policies/baseline.stella
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stella policy simulate P-baseline --candidate 1 --sbom sbom:sample-prod
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```
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## Compliance checklist
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- [ ] Policy compiled via `stella policy lint` without diagnostics.
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- [ ] Simulation diff reviewed against golden SBOM set.
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- [ ] Approval note documents rationale before promoting to production.
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- [ ] EOL runtime tags kept up to date in SBOM metadata.
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- [ ] VEX vendor allow-list reviewed quarterly.
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---
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*Last updated: 2025-10-26.*
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