4953 Windows Firewall ignored a rule because it could not be parsed
Written when the Windows Firewall could not parse a rule and ignored it. It indicates that, due to a corrupt or inconsistent rule definition, a defense may not be in effect.
Overview
The subcategory is Audit MPSSVC Rule-Level Policy Change. It is generated when the firewall cannot correctly parse a rule and ignores it. The cause is a corrupt or malformed rule definition.
How it is triggered
- When a corrupt or malformed firewall rule is loaded and parsing fails.
Security review points
- A rule that cannot be parsed is not applied, meaning an intended defense may be missing. Check whether an important rule was disabled by a parse failure.
- Corrupt rule definitions are mostly fault-induced, but also consider the slight possibility of a technique that deliberately makes rules unparseable by tampering with the rule store.
Notes for log review
- It is rare. When it occurs, check the profile of the rule that failed to parse and the health of the rule store.
- Together with 4951/4952, understand gaps in rule application.
Key fields
| Field | Meaning |
|---|---|
| Ignored rule | The rule that failed to parse |