One of Microsoft's latest security updates does not fix the vulnerability it was meant to patch.

This is according to Panda Security, which says tat Update MS09-008, released yesterday by Microsoft, was designed to fix four vulnerabilities in Windows DNS server and WINS server. However, an unpatched flaw has been detected in the DNS server, more specifically in WPAD (Web Proxy Autodiscovery Protocol ) registration.
WPAD is a service that allows automatic detection of proxy settings without user intervention.
Clients have to download WPAD entries from the DNS server, and those entries that could be affected by the "man-in-the-middle" attack. An attacker that exploited this vulnerability successfully could redirect users' traffic through a malicious proxy.
"If an attacker manages to redirect targeted users to a malicious proxy they could obtain private information and redirect them to malicious pages in order to infect them with malware or monitor their Internet movements," explains Jeremy Matthews, head of Panda's sub-Saharan operations.