[Plugin: WP-Syntax] security problem in folder contrib?

Some days ago my blog was attacked probably by hashscanner, they inserted some malware code in core files of wordpress… Now I am searching where is the problem and in the possibles causes there is this exploit:
wp-syntax-exploit
Now I removed the folder, 🙂
bye

http://ww.wp.xz.cn/extend/plugins/wp-syntax/