When an SRX Series device is configured to use HTTP/HTTPS pass-through authentication services, a client sending authentication credentials in the initial HTTP/HTTPS session is at risk that these credentials may be captured during follow-on HTTP/HTTPS requests by a malicious actor through a man-in-the-middle attack or by authentic servers subverted by malicious actors. FTP, and Telnet pass-through authentication services are not affected. Affected releases are Juniper Networks SRX Series: 12.1X46 versions prior to 12.1X46-D67 on SRX Series; 12.3X48 versions prior to 12.3X48-D25 on SRX Series; 15.1X49 versions prior to 15.1X49-D35 on SRX Series.
https://kb.juniper.net/JSA10858