System V Init (init.d) Executed Binary from Unusual Location Sync RTA (#3944)

Co-authored-by: shashank-elastic <91139415+shashank-elastic@users.noreply.github.com>

rta/linux_persistence_initd_unusual_binary_execution.py

@@ -0,0 +1,51 @@
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. Licensed under the Elastic License
+# 2.0; you may not use this file except in compliance with the Elastic License
+# 2.0.
+
+from . import common
+from . import RtaMetadata
+
+metadata = RtaMetadata(
+    uuid="0560d795-bdd6-4a91-97ad-8e2c2d8143ef",
+    platforms=["linux"],
+    endpoint=[
+        {
+            "rule_name": "System V Init (init.d) Executed Binary from Unusual Location",
+            "rule_id": "879c083c-e2d9-4f75-84f2-0f1471d915a8"
+        }
+    ],
+    techniques=["T1037"],
+)
+
+
+@common.requires_os(*metadata.platforms)
+def main():
+
+    # Path for the fake initd script
+    initd_script = "/etc/init.d/rta"
+
+    # Create fake executable
+    masquerade = "/dev/shm/evil"
+    source = common.get_path("bin", "linux.ditto_and_spawn")
+    common.copy_file(source, masquerade)
+
+    # Create a fake script that executes the fake binary
+    with open(initd_script, 'w') as script:
+        script.write('#!/bin/bash\n')
+        script.write('/dev/shm/evil\n')
+
+    # Make the script executable
+    common.execute(['chmod', '+x', initd_script])
+
+    # Execute the fake script
+    common.log("Launching fake initd script")
+    common.execute([initd_script], timeout=5, kill=True, shell=True)
+
+    # Cleanup
+    common.remove_file(initd_script)
+    common.remove_file(masquerade)
+
+
+if __name__ == "__main__":
+    exit(main())