Bing SearchByImage SSRF Exfiltration

Detects browser connections to the Bing Search by Image endpoint, which can be exploited as a Server-Side Request Forgery (SSRF) proxy to bypass Content Security Policies (CSP) and exfiltrate data, as seen in the SearchLeak attack. The rule specifically looks for connections to 'bing.com/images/searchbyimage' that also include the 'imgurl=' or 'imgurl%3d' parameter, indicating an attempt to use the server-side fetch functionality.