diff --git a/lib/core/common.py b/lib/core/common.py
index 20958e540..dc59a642c 100644
--- a/lib/core/common.py
+++ b/lib/core/common.py
@@ -60,6 +60,7 @@ from lib.core.settings import PLATFORM
 from lib.core.settings import SITE
 from lib.core.settings import SQL_STATEMENTS
 from lib.core.settings import SUPPORTED_DBMS
+from lib.core.settings import UNKNOWN_DBMS_VERSION
 from lib.core.settings import VERSION_STRING
 from lib.core.settings import DUMP_NEWLINE_MARKER
 from lib.core.settings import DUMP_CR_MARKER
@@ -203,7 +204,7 @@ def formatDBMSfp(versions=None):
     while versions and None in versions:
         versions.remove(None)
 
-    if not versions and kb.dbmsVersion and kb.dbmsVersion[0] != "Unknown" and kb.dbmsVersion[0] != None:
+    if not versions and kb.dbmsVersion and kb.dbmsVersion[0] != UNKNOWN_DBMS_VERSION and kb.dbmsVersion[0] != None:
         versions = kb.dbmsVersion
 
     if isinstance(versions, basestring):
@@ -1719,7 +1720,7 @@ def removeDynamicContent(page):
 def isDBMSVersionAtLeast(version):
     retVal = None
 
-    if kb.dbmsVersion and kb.dbmsVersion[0] != "Unknown" and kb.dbmsVersion[0] != None:
+    if kb.dbmsVersion and kb.dbmsVersion[0] != UNKNOWN_DBMS_VERSION and kb.dbmsVersion[0] != None:
         value = kb.dbmsVersion[0].replace(" ", "")
 
         if isinstance(value, basestring):
diff --git a/lib/core/option.py b/lib/core/option.py
index abd799ab2..81f2340f5 100644
--- a/lib/core/option.py
+++ b/lib/core/option.py
@@ -73,6 +73,7 @@ from lib.core.settings import ACCESS_ALIASES
 from lib.core.settings import FIREBIRD_ALIASES
 from lib.core.settings import MAXDB_ALIASES
 from lib.core.settings import SYBASE_ALIASES
+from lib.core.settings import UNKNOWN_DBMS_VERSION
 from lib.core.update import update
 from lib.parse.configfile import configFileParser
 from lib.parse.payloads import loadPayloads
@@ -1144,7 +1145,7 @@ def __setKnowledgeBaseAttributes():
     kb.dbmsDetected    = False
 
     # Active (extensive) back-end DBMS fingerprint
-    kb.dbmsVersion     = [ "Unknown" ]
+    kb.dbmsVersion     = [ UNKNOWN_DBMS_VERSION ]
 
     kb.dep             = None
     kb.docRoot         = None
diff --git a/lib/core/session.py b/lib/core/session.py
index 1feaadc97..5f0136333 100644
--- a/lib/core/session.py
+++ b/lib/core/session.py
@@ -25,6 +25,7 @@ from lib.core.settings import MSSQL_ALIASES
 from lib.core.settings import MYSQL_ALIASES
 from lib.core.settings import PGSQL_ALIASES
 from lib.core.settings import ORACLE_ALIASES
+from lib.core.settings import UNKNOWN_DBMS_VERSION
 
 def safeFormatString(value):
     retVal = value
@@ -361,7 +362,7 @@ def resumeConfKb(expression, url, value):
     elif expression == "DBMS" and url == conf.url:
         dbms        = unSafeFormatString(value[:-1])
         dbms        = dbms.lower()
-        dbmsVersion = ["Unknown"]
+        dbmsVersion = [UNKNOWN_DBMS_VERSION]
 
         logMsg = "resuming back-end DBMS '%s' " % dbms
         logMsg += "from session file"
diff --git a/lib/core/settings.py b/lib/core/settings.py
index 8515baa7a..52354d941 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -49,6 +49,8 @@ DUMP_STOP_MARKER    = "__STOP__"
 PAYLOAD_DELIMITER   = "\x00"
 CHAR_INFERENCE_MARK = "%c"
 
+UNKNOWN_DBMS_VERSION = "Unknown"
+
 # suffix used for naming meta databases in DBMS(es) without explicit database name
 METADB_SUFFIX       = "_masterdb"
 
diff --git a/plugins/dbms/mssqlserver/fingerprint.py b/plugins/dbms/mssqlserver/fingerprint.py
index 19635a3e4..0eb7b98c1 100644
--- a/plugins/dbms/mssqlserver/fingerprint.py
+++ b/plugins/dbms/mssqlserver/fingerprint.py
@@ -19,6 +19,7 @@ from lib.core.data import logger
 from lib.core.enums import DBMS
 from lib.core.session import setDbms
 from lib.core.settings import MSSQL_ALIASES
+from lib.core.settings import UNKNOWN_DBMS_VERSION
 from lib.request import inject
 from lib.request.connect import Connect as Request
 
@@ -132,7 +133,7 @@ class Fingerprint(GenericFingerprint):
 
                         break
 
-            if not kb.dbmsVersion or kb.dbmsVersion == ["Unknown"]:
+            if not kb.dbmsVersion or kb.dbmsVersion == [UNKNOWN_DBMS_VERSION]:
                 for version, check in [\
                         ("2000", "HOST_NAME()=HOST_NAME()"),\
                         ("2005", "XACT_STATE()=XACT_STATE()"),\
diff --git a/plugins/dbms/mysql/fingerprint.py b/plugins/dbms/mysql/fingerprint.py
index 092efd4c7..fbd1d789b 100644
--- a/plugins/dbms/mysql/fingerprint.py
+++ b/plugins/dbms/mysql/fingerprint.py
@@ -22,6 +22,7 @@ from lib.core.enums import DBMS
 from lib.core.enums import PLACE
 from lib.core.session import setDbms
 from lib.core.settings import MYSQL_ALIASES
+from lib.core.settings import UNKNOWN_DBMS_VERSION
 from lib.request import inject
 from lib.request.connect import Connect as Request
 
@@ -144,7 +145,7 @@ class Fingerprint(GenericFingerprint):
 
         if ((kb.dbms is not None and kb.dbms.lower() in MYSQL_ALIASES) \
            or conf.dbms in MYSQL_ALIASES) and kb.dbmsVersion and \
-           kb.dbmsVersion[0] != "Unknown":
+           kb.dbmsVersion[0] != UNKNOWN_DBMS_VERSION:
             kb.dbmsVersion[0] = kb.dbmsVersion[0].replace(">", "")
             kb.dbmsVersion[0] = kb.dbmsVersion[0].replace("=", "")
             kb.dbmsVersion[0] = kb.dbmsVersion[0].replace(" ", "")