diff --git a/src/core/zowe/core_for_zowe_sdk/logger.py b/src/core/zowe/core_for_zowe_sdk/logger.py
index 7c4a5029..fa63159a 100644
--- a/src/core/zowe/core_for_zowe_sdk/logger.py
+++ b/src/core/zowe/core_for_zowe_sdk/logger.py
@@ -36,8 +36,14 @@ class Log:
     """
 
     dirname: str = os.path.join(os.path.expanduser("~"), ".zowe/logs")
-    os.makedirs(dirname, exist_ok=True)
-    file_handler: logging.FileHandler = logging.FileHandler(os.path.join(dirname, "python_sdk_logs.log"))
+    os.makedirs(dirname, mode=0o700, exist_ok=True)
+    os.chmod(dirname, 0o700)
+    __log_filename: str = os.path.join(dirname, "python_sdk_logs.log")
+
+    __log_fd = os.open(__log_filename, os.O_CREAT | os.O_APPEND, 0o600)
+    os.close(__log_fd)
+    os.chmod(__log_filename, 0o600)
+    file_handler: logging.FileHandler = logging.FileHandler(__log_filename)
     file_handler.setLevel(logging.INFO)
     file_handler.setFormatter(
         logging.Formatter("[%(asctime)s] [%(levelname)s] [%(name)s] - %(message)s", "%m/%d/%Y %I:%M:%S %p")
diff --git a/src/core/zowe/core_for_zowe_sdk/request_handler.py b/src/core/zowe/core_for_zowe_sdk/request_handler.py
index f3759d75..3b7d308a 100644
--- a/src/core/zowe/core_for_zowe_sdk/request_handler.py
+++ b/src/core/zowe/core_for_zowe_sdk/request_handler.py
@@ -10,6 +10,7 @@
 Copyright Contributors to the Zowe Project.
 """
 
+import copy
 from typing import Union, Any
 from requests import Response
 
@@ -19,6 +20,30 @@
 from .exceptions import InvalidRequestMethod, RequestFailed, UnexpectedStatus
 from .logger import Log
 
+SENSITIVE_HEADERS = {"authorization", "cookie", "x-csrf-zosmf-header"}
+REDACTED = "<redacted>"
+
+
+def _redact_headers(headers: Any) -> dict[str, Any]:
+    """Return a copy of the given headers with sensitive values redacted."""
+    if not headers:
+        return dict(headers) if headers else {}
+    return {key: (REDACTED if key.lower() in SENSITIVE_HEADERS else value) for key, value in headers.items()}
+
+
+def _redact_request_arguments(request_arguments: dict[str, Any]) -> dict[str, Any]:
+    """Return a copy of request_arguments safe to log, with credentials and headers redacted."""
+    safe_arguments = copy.copy(request_arguments)
+    if "auth" in safe_arguments:
+        safe_arguments["auth"] = REDACTED
+    if "headers" in safe_arguments:
+        safe_arguments["headers"] = _redact_headers(safe_arguments["headers"])
+    if "json" in safe_arguments:
+        safe_arguments["json"] = REDACTED
+    if "data" in safe_arguments:
+        safe_arguments["data"] = REDACTED
+    return safe_arguments
+
 
 class RequestHandler:
     """
@@ -69,7 +94,9 @@ def perform_request(
         self.__request_arguments = request_arguments
         self.__expected_code = expected_code
         self.__logger.debug(
-            f"Request method: {self.__method}, Request arguments: {self.__request_arguments}, Expected code: {expected_code}"
+            f"Request method: {self.__method}, "
+            f"Request arguments: {_redact_request_arguments(self.__request_arguments)}, "
+            f"Expected code: {expected_code}"
         )
         self.__validate_method()
         self.__send_request(stream=stream)
@@ -129,8 +156,8 @@ def __validate_response(self) -> None:
                 raise UnexpectedStatus(self.__expected_code, self.__response.status_code, self.__response.text)
         else:
             output_str = str(self.__response.request.url)
-            output_str += "\n" + str(self.__response.request.headers)
-            output_str += "\n" + str(self.__response.request.body)
+            output_str += "\n" + str(_redact_headers(self.__response.request.headers))
+            output_str += "\n" + (REDACTED if self.__response.request.body else "")
             output_str += "\n" + str(self.__response.text)
             self.__logger.error(
                 f"HTTP Request has failed with status code {self.__response.status_code}. \n {output_str}"
diff --git a/tests/unit/core/test_logger.py b/tests/unit/core/test_logger.py
index c0c049ac..c704e84f 100644
--- a/tests/unit/core/test_logger.py
+++ b/tests/unit/core/test_logger.py
@@ -2,6 +2,8 @@
 
 # Including necessary paths
 import logging
+import os
+import stat
 
 from pyfakefs.fake_filesystem_unittest import TestCase
 from zowe.core_for_zowe_sdk.logger import Log
@@ -76,3 +78,13 @@ def test_file_handler(self):
 
         Log.set_file_output_level(logging.ERROR)
         self.assertEqual(logging.ERROR, Log.file_handler.level)
+
+    def test_log_directory_and_file_are_owner_only(self):
+        """The log directory and file should not be readable/writable by group or others, since log
+        content may include request/response details."""
+        dir_mode = stat.S_IMODE(os.stat(Log.dirname).st_mode)
+        self.assertEqual(dir_mode, 0o700)
+
+        log_file = os.path.join(Log.dirname, "python_sdk_logs.log")
+        file_mode = stat.S_IMODE(os.stat(log_file).st_mode)
+        self.assertEqual(file_mode, 0o600)
diff --git a/tests/unit/core/test_request_handler.py b/tests/unit/core/test_request_handler.py
index fe2364b5..f3bbd967 100644
--- a/tests/unit/core/test_request_handler.py
+++ b/tests/unit/core/test_request_handler.py
@@ -76,3 +76,44 @@ def test_empty_text(self, mock_send_request):
         request_handler = RequestHandler(self.session_arguments)
         response = request_handler.perform_request("GET", {"url": "https://www.zowe.org"})
         self.assertTrue(response == None)
+
+    @mock.patch("logging.Logger.debug")
+    @mock.patch("requests.Session.send")
+    def test_debug_log_redacts_credentials(self, mock_send_request, mock_logger_debug: mock.MagicMock):
+        """The DEBUG request-arguments dump should never contain raw auth or header secrets."""
+        mock_send_request.return_value = mock.Mock(status_code=200)
+        request_handler = RequestHandler(self.session_arguments)
+        request_handler.perform_request(
+            "GET",
+            {
+                "url": "https://www.zowe.org",
+                "auth": ("user", "super-secret-password"),
+                "headers": {"Authorization": "Bearer super-secret-token", "Cookie": "LtpaToken2=super-secret-cookie"},
+                "json": {"password": "super-secret-password"},
+            },
+            stream=True,
+        )
+        debug_message = mock_logger_debug.call_args[0][0]
+        self.assertNotIn("super-secret-password", debug_message)
+        self.assertNotIn("super-secret-token", debug_message)
+        self.assertNotIn("super-secret-cookie", debug_message)
+
+    @mock.patch("logging.Logger.error")
+    @mock.patch("requests.Session.send")
+    def test_error_log_and_exception_redact_credentials(self, mock_send_request, mock_logger_error: mock.MagicMock):
+        """A failed request should not leak the Authorization/Cookie headers or body into logs or the raised exception."""
+        mock_request = mock.Mock(
+            url="https://www.zowe.org",
+            headers={"Authorization": "Basic super-secret-basic-auth", "Cookie": "LtpaToken2=super-secret-cookie"},
+            body="super-secret-body-content",
+        )
+        mock_send_request.return_value = mock.Mock(ok=False, status_code=500, text="failure", request=mock_request)
+        request_handler = RequestHandler(self.session_arguments)
+        with self.assertRaises(exceptions.RequestFailed) as ctx:
+            request_handler.perform_request("GET", {"url": "https://www.zowe.org"}, stream=True)
+
+        error_message = mock_logger_error.call_args[0][0]
+        exception_message = str(ctx.exception)
+        for secret in ("super-secret-basic-auth", "super-secret-cookie", "super-secret-body-content"):
+            self.assertNotIn(secret, error_message)
+            self.assertNotIn(secret, exception_message)