diff --git a/src/bnetd/account.cpp b/src/bnetd/account.cpp
index b1cff2792..ee4f6c056 100644
--- a/src/bnetd/account.cpp
+++ b/src/bnetd/account.cpp
@@ -53,6 +53,7 @@
 #include "storage.h"
 #include "common/flags.h"
 #include "common/xalloc.h"
+#include "common/xstring.h"
 #include "common/setup_after.h"
 
 namespace pvpgn
@@ -570,14 +571,7 @@ namespace pvpgn
 
 
 			if (tname = account_get_name(account)) {
-				char temp[MAX_USERNAME_LEN];
-				for (i = 0; i < std::strlen(tname); i++) {
-					temp[i] = tname[i];
-					if (isupper((int)temp[i])) {
-						temp[i] = tolower((int)temp[i]);
-					}
-				}
-				if (strstr(temp, vague_username)) {
+				if (find_substr((char*)tname, vague_username)) {
 					return tname;
 				}
 				return NULL;
diff --git a/src/common/xstring.cpp b/src/common/xstring.cpp
index 1f1670d93..890f431c0 100644
--- a/src/common/xstring.cpp
+++ b/src/common/xstring.cpp
@@ -27,6 +27,7 @@
 #include <iomanip>
 
 #include "compat/strdup.h"
+#include "compat/strcasecmp.h"
 #include "common/xalloc.h"
 #include "common/setup_after.h"
 
@@ -331,4 +332,30 @@ namespace pvpgn
 	}
 
 
+	// search substring in input string
+	// (case insensitive)
+	extern bool find_substr(char * input, const char * find)
+	{
+		char c1[2], c2[2];
+		bool is_found = false;
+		int pos = 0;
+		int b = true;
+		for (int i = 0; i < strlen(input); i++)
+		{
+			c1[0] = input[i]; c1[1] = '\0';
+			c2[0] = find[pos]; c2[1] = '\0';
+			if (strcasecmp(c1, c2) == 0)
+			{
+				if (pos == strlen(find) - 1)
+				{
+					is_found = true;
+					break;
+				}
+				pos++;
+			}
+			else
+				pos = 0;
+		}
+		return is_found;
+	}
 }
diff --git a/src/common/xstring.h b/src/common/xstring.h
index 01c4d112e..924022948 100644
--- a/src/common/xstring.h
+++ b/src/common/xstring.h
@@ -35,6 +35,7 @@ namespace pvpgn
 	extern char *		str_strip_affix(char * str, char const * affix);
 	extern char *str_replace(char *orig, char *rep, char *with);
 	extern std::string str_replace_nl(char const * text);
+	extern bool find_substr(char * input, const char * find);
 
 	#define safe_toupper(X) (std::islower((int)X)?std::toupper((int)X):(X))