diff --git a/plugins/dbms/access/syntax.py b/plugins/dbms/access/syntax.py
index 36a4f6184..494eff917 100644
--- a/plugins/dbms/access/syntax.py
+++ b/plugins/dbms/access/syntax.py
@@ -27,7 +27,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/firebird/syntax.py b/plugins/dbms/firebird/syntax.py
index 3928f3d75..a601470e0 100644
--- a/plugins/dbms/firebird/syntax.py
+++ b/plugins/dbms/firebird/syntax.py
@@ -29,7 +29,7 @@ class Syntax(GenericSyntax):
                     index = expression[firstIndex:].find("'")
 
                     if index == -1:
-                        break
+                        raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression
 
                     lastIndex = firstIndex + index
                     old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/mssqlserver/syntax.py b/plugins/dbms/mssqlserver/syntax.py
index c3442096d..ca3559612 100644
--- a/plugins/dbms/mssqlserver/syntax.py
+++ b/plugins/dbms/mssqlserver/syntax.py
@@ -27,7 +27,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException("Unenclosed ' in '%s'" % expression)
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/mysql/syntax.py b/plugins/dbms/mysql/syntax.py
index 871e5c7d7..4fa3bc98e 100644
--- a/plugins/dbms/mysql/syntax.py
+++ b/plugins/dbms/mysql/syntax.py
@@ -27,7 +27,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/oracle/syntax.py b/plugins/dbms/oracle/syntax.py
index ac915ddd2..141beeefd 100644
--- a/plugins/dbms/oracle/syntax.py
+++ b/plugins/dbms/oracle/syntax.py
@@ -26,7 +26,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/postgresql/syntax.py b/plugins/dbms/postgresql/syntax.py
index 3c432f470..833ffe6ec 100644
--- a/plugins/dbms/postgresql/syntax.py
+++ b/plugins/dbms/postgresql/syntax.py
@@ -27,7 +27,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/sqlite/syntax.py b/plugins/dbms/sqlite/syntax.py
index 9d8c01ac8..a7030565f 100644
--- a/plugins/dbms/sqlite/syntax.py
+++ b/plugins/dbms/sqlite/syntax.py
@@ -30,7 +30,7 @@ class Syntax(GenericSyntax):
                     index = expression[firstIndex:].find("''")
 
                     if index == -1:
-                        break
+                        raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression.replace("''", "'")
 
                     lastIndex = firstIndex + index
                     old = "''%s''" % expression[firstIndex:lastIndex]
diff --git a/plugins/dbms/sybase/syntax.py b/plugins/dbms/sybase/syntax.py
index c3442096d..ca3559612 100644
--- a/plugins/dbms/sybase/syntax.py
+++ b/plugins/dbms/sybase/syntax.py
@@ -27,7 +27,7 @@ class Syntax(GenericSyntax):
                 index = expression[firstIndex:].find("'")
 
                 if index == -1:
-                    break
+                    raise sqlmapSyntaxException("Unenclosed ' in '%s'" % expression)
 
                 lastIndex = firstIndex + index
                 old = "'%s'" % expression[firstIndex:lastIndex]