Merge pull request #1283 from mandiant/fix/issue-1282

better detect invalid rules

CHANGELOG.md

@@ -82,6 +82,7 @@
 - dotnet: address unhandled exceptions with improved type checking #1230 @mike-hunhoff
 - fix import-to-ida script formatting #1208 @williballenthin
 - render: fix verbose rendering of scopes #1263 @williballenthin
+- rules: better detect invalid rules #1282 @williballenthin
 - show-features: better render strings with embedded whitespace #1267 @williballenthin
 
 ### capa explorer IDA Pro plugin

capa/rules.py

@@ -29,6 +29,7 @@ from typing import Any, Set, Dict, List, Tuple, Union, Iterator
 import yaml
 import pydantic
 import ruamel.yaml
+import yaml.parser
 
 import capa.perf
 import capa.engine as ceng
@@ -836,6 +837,8 @@ class Rule:
                 raise InvalidRuleWithPath(path, str(e)) from e
             except pydantic.ValidationError as e:
                 raise InvalidRuleWithPath(path, str(e)) from e
+            except yaml.parser.ParserError as e:
+                raise InvalidRuleWithPath(path, str(e)) from e
 
     def to_yaml(self) -> str:
         # reformat the yaml document with a common style.