Sync RTA Potential Persistence via Direct Crontab Modification (#4069)

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

rta/linux_persistence_direct_crontab_modification.py

@@ -0,0 +1,53 @@
+# 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.
+
+import sys
+from pathlib import Path
+
+from . import RtaMetadata, common
+
+metadata = RtaMetadata(
+    uuid="a1286125-bf4b-40bb-819a-b7c5de83fafb",
+    platforms=["linux"],
+    endpoint=[
+        {
+            "rule_name": "Potential Persistence via Direct Crontab Modification",
+            "rule_id": "b3bcbab6-e216-4d70-bdee-2b69affbb386",
+        },
+    ],
+    techniques=["T1053"],
+)
+
+
+@common.requires_os(*metadata.platforms)
+def main() -> None:
+    # Path for the fake script
+    rta_script = "/dev/shm/rta"
+
+    # Create fake executable
+    masquerade = "/tmp/crontab"
+    source = common.get_path("bin", "linux.ditto_and_spawn")
+    common.copy_file(source, masquerade)
+    common.execute(["chmod", "+x", masquerade])
+
+    # Create a fake script that executes the fake binary
+    with Path(rta_script).open("w", encoding="utf-8") as script:
+        script.write("#!/bin/bash\n")
+        script.write("/tmp/crontab -\n")
+
+    # Make the script executable
+    common.execute(["chmod", "+x", rta_script])
+
+    # Execute the fake script
+    common.log("Launching fake script")
+    common.execute([rta_script], timeout=5, kill=True, shell=True)  # noqa: S604
+
+    # Cleanup
+    common.remove_file(rta_script)
+    common.remove_file(masquerade)
+
+
+if __name__ == "__main__":
+    sys.exit(main())