Malicious code masquerading as a trusted application could <A HREF="http://news.zdnet.com/2100-1009_22-5886488.html?tag=zdnn.alert">trick a ZoneAlarm firewall</A> into letting it connect to the Internet, security experts have warned. The issue affects the popular free ZoneAlarm firewall and default installations of version 5.5 and earlier of the paid product, maker Zone Labs said in a security advisory. Default installations of the Check Point Integrity Client are also affected, but the paid ZoneAlarm 6.0 products, released in July are not.