Sync RTA Renice or Ulimit Execution from Unusual Parent (#4203)

Co-authored-by: shashank-elastic <[email protected]>

(cherry picked from commit ae2adc7)

Author: protectionsmachine

rta/linux_execution_renice_ulimit.py

@@ -0,0 +1,46 @@
+# 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 . import RtaMetadata, common
+
+metadata = RtaMetadata(
+    uuid="9e7ec69a-50cb-4bce-8ace-50e4e6f0199d",
+    platforms=["linux"],
+    endpoint=[
+        {
+            "rule_name": "Renice or Ulimit Execution",
+            "rule_id": "57ed0e43-643a-47f3-936e-138dc6f480da",
+        },
+    ],
+    techniques=["T1059"],
+)
+
+
+@common.requires_os(*metadata.platforms)
+def main() -> None:
+    common.log("Creating a fake executable..")
+    masquerade = "/dev/shm/evil"
+
+    source = common.get_path("bin", "netcon_exec_chain.elf")
+    common.copy_file(source, masquerade)
+    common.execute(["chmod", "+x", masquerade])
+
+    masquerade2 = "/dev/shm/renice"
+    common.copy_file(source, masquerade2)
+    common.log("Granting execute permissions...")
+    common.execute(["chmod", "+x", masquerade2])
+
+    commands = [masquerade, "exec", "-c", "/dev/shm/renice"]
+    common.execute([*commands], timeout=5, kill=True)
+    common.log("Cleaning...")
+    common.remove_file(masquerade)
+    common.remove_file(masquerade2)
+    common.log("Simulation successfull!")
+
+
+if __name__ == "__main__":
+    sys.exit(main())