http://www.squid-cache.org/Doc/FAQ/FAQ-23.html
Use pam_auth module for authentication. In redhat systems located here:
chmod u+s /usr/lib/squid/pam_auth
So in squid.conf it will be:
auth_param basic program /usr/lib/squid/pam_auth
Also create a file if it doesn't exist called /etc/pam.d/squid containing:
Code:
#%PAM-1.0
auth required pam_stack.so service=system-auth
account required pam_stack.so service=system-auth