Add folder enumeration signature for ransomware detection

modules/signatures/windows/discovery_filesystem.py

@@ -0,0 +1,45 @@
+# Copyright (C) 2026 Kevin Ross
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from lib.cuckoo.common.abstracts import Signature
+
+class FolderEnumeration(Signature):
+    name = "folder_enumeration"
+    description = "Systematically searches multiple user directories using wildcards, common in ransomware/wipers/infostealers"
+    severity = 3
+    confidence = 70
+    categories = ["ransomware", "wiper", "infostealer", "discovery"]
+    authors = ["Kevin Ross"]
+    minimum = "1.3"
+    evented = True
+    enabled = True
+    ttps = ["T1083"]
+
+    def run(self):
+        targeted_folders = set()
+        pattern = r"(?i).*?(Users|Documents|Desktop|Downloads|Music|Videos|Pictures|AppData).*\\\*.*"   
+        matches = self.check_file(pattern=pattern, regex=True, all=True)
+
+        if matches:
+            for match in matches:
+                folder = match.rsplit('\\', 1)[0].lower()
+                if folder not in targeted_folders:
+                    targeted_folders.add(folder)
+                    self.data.append({"target_folder": match})
+
+        if len(targeted_folders) > 10:
+            return True
+
+        return False