Companies that use security products to inspect HTTPS traffic might inadvertently make their users’ encrypted connections less secure and expose them to man-in-the-middle attacks, the U.S. Computer Emergency Readiness Team warns.
US-CERT, a division of the Department of Homeland Security, published an advisory after a recent survey showed that HTTPS inspection products don’t mirror the security attributes of the original connections between clients and servers.
HTTPS inspection checks the encrypted traffic coming from an HTTPS site to make sure it doesn’t contain threats or malware. It’s performed by intercepting a client’s connection to an HTTPS server, establishing the connection on the client’s behalf and then re-encrypting the traffic sent to the client with a different, locally generated certificate. Products that do this essentially act as man-in-the-middle proxies.