diff --git a/lib/core/settings.py b/lib/core/settings.py
index 4164e6cce..51dfa4669 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -33,6 +33,10 @@ LOGGER_HANDLER.setFormatter(FORMATTER)
 LOGGER.addHandler(LOGGER_HANDLER)
 LOGGER.setLevel(logging.WARN)
 
+# error based injection
+ERROR_SPACE        = "%c%c%c" % (58, 95, 58)
+ERROR_EMPTY_CHAR   = "%c%c%c" % (58, 120, 58)
+
 # System variables
 IS_WIN             = subprocess.mswindows
 # The name of the operating system dependent module imported. The following
diff --git a/lib/request/inject.py b/lib/request/inject.py
index 4d1dc2a4d..6bcd67838 100644
--- a/lib/request/inject.py
+++ b/lib/request/inject.py
@@ -27,6 +27,8 @@ from lib.core.data import conf
 from lib.core.data import kb
 from lib.core.data import logger
 from lib.core.data import queries
+from lib.core.settings import ERROR_SPACE
+from lib.core.settings import ERROR_EMPTY_CHAR
 from lib.core.unescaper import unescaper
 from lib.request.connect import Connect as Request
 from lib.request.direct import direct
@@ -359,7 +361,7 @@ def __goError(expression, resumeValue=True):
     if match:
         output = match.group('result')
         if output:
-            output = output.replace("%c%c%c" % (58, 95, 58), " ").replace("%c%c%c" % (58, 120, 58), "") #':_:' -> EMPTY CHAR, ':x:' -> SPACE CHAR
+            output = output.replace(ERROR_SPACE, " ").replace(ERROR_EMPTY_CHAR, "")
 
             if kb.misc.testedDbms == 'MySQL':
                 output = output[:-1]