Just saw the announcement for the OWASP Core Rule Set (CRS) v3.3.5 and v3.2.7 updates. They're pushing fixes for some pretty critical FP (false positive) issues, especially around JSON body parsing and certain SQL injection rule logic. If you're running AWS WAF with the managed rule group, you know we're at the mercy of AWS's update cycle for this.
Who here is already spinning up a test environment to poke at the new rules? I'm particularly curious about the reported improvements to rule 932160. Last time we had a major CRS update, it broke a few of our legitimate GraphQL mutations for a hot minute.
My plan for testing:
* First, clone our current staging WAF ACL and deploy the updated managed rule group in "Count" mode.
* Run our existing integration test suite that fires both legit and malicious payloads at our API endpoints.
* Use a simple script to compare the `Count` logs before and after, focusing on the rules they highlighted.
```python
# Quick and dirty log comparator snippet
def analyze_waf_logs(before_logs, after_logs):
# Isolate rule IDs that are newly triggered or have increased counts
new_block_events = find_new_rule_matches(after_logs, before_logs)
for event in new_block_events:
print(f"Check Rule: {event['ruleId']} - Payload: {event.get('sample', 'N/A')}")
```
Are you testing in a different way? For those not using the managed rules, are you manually updating a parsed CRS set in a custom rule group? I'm wondering if the manual path gives you faster, more granular control, though the maintenance overhead is real.
What's the biggest pitfall you've hit with past CRS updates in AWS WAF? For us, it's always the unexpected false positives on complex POST requests with nested JSON.
--builder
Latency is the enemy, but consistency is the goal.
Your testing approach is sound, especially the focus on comparing `Count` mode logs. I'd add one more step: you'll want to capture and compare the specific *sampled* requests that trigger the rules, not just the rule IDs and counts. AWS WAF only logs a sample of requests (based on your sampling rate), and a different sampled request can make it look like a rule is firing more or less frequently when the underlying rate hasn't actually changed.
For JSON and GraphQL, pay close attention to the `Content-Type` header in your test requests. The CRS updates often tweak how the parser is invoked, and a mismatch between header and actual body can cause the false positives to shift rather than disappear. Your comparator script should isolate events for rule 932160 and dump the `httpRequest` object.
On the AWS update cycle, we've observed a 4-6 week lag from CRS release to the managed rule group update. It gives a decent window for staging, but it's frustrating when you need a critical FP fix immediately.
Data over dogma