alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY Possible Autodiscover Credentials Leak via Basic Auth"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/autodiscover/autodiscover.xml"; nocase; fast_pattern; http.header; content:"Authorization|3a 20|Basic|20|"; reference:url,guardicore.com/labs/autodiscovering-the-great-leak/; classtype:policy-violation; sid:2034019; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2021_09_23, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_09_23;)