* BanSubstrings scanner to escape special characters

Author: asofter

docs/changelog.md

@@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 -
 
 ### Fixed
--
+- `BanSubstrings` scanner to handle substrings with special characters.
 
 ### Changed
 -

llm_guard/input_scanners/ban_substrings.py

@@ -26,7 +26,7 @@ def match(self, text: str, substring: str) -> bool:
             return substring in text
 
         if self == MatchType.WORD:
-            return re.search(r"\b" + substring + r"\b", text) is not None
+            return re.search(r"\b" + re.escape(substring) + r"\b", text) is not None
 
 
 class BanSubstrings(Scanner):

tests/input_scanners/test_ban_substrings.py

@@ -23,6 +23,13 @@
             False,
             1.0,
         ),
+        (
+            "My special characters are: !@#$%^&*()_+",
+            False,
+            "My special characters are: !@#$%^&*()_+",
+            True,
+            0.0,
+        )
     ],
 )
 def test_scan(prompt, redact, expected_prompt, expected_valid, expected_score):