Hi mahmoud
The version you are currently using does support TLS1.2 but also supports older SSL versions. There is a shell command for stopping the use of specific SSL versions, however this command wont survive a reboot of the firewall.
1. From the root shell:
root@junos% vi /jail/var/etc/httpd.conf
Change the default config, something similar to "SSLProtocol ALL -SSLV2" to "SSLProtocol TLSv1"
2. Find the process ID (pid) of httpd and kill/restart it:
root@junos% ps auxw | grep httpd
root@junos% kill -9 (pid of httpd)
OR
root@junos% kill -HUP (pid of httpd)
*Note: This change will not survive after reboots.
Additionally, executing the 'restart web-management' CLI command will restart the httpd-gk process which will regenerate the default httpd.conf file, and overwrite the manual changes.
The best solution is to upgrade to version 12.3X48-D55 or newer because "In SRX devices that run Junos OS releases 12.3X48-D55 and later, Transport Layer Security (TLS) versions prior to TLSv1.2 are not supported."
Reference: https://kb.juniper.net/InfoCenter/index?page=content&id=KB32921&cat=SRX_SERIES&actp=LIST
Hope this helps and please mark as "Solution Accepted" if it applies.