Paranoid Penguin - Building a Secure Squid Web Proxy, Part III
Setting ACLs, running Squid with nonroot privileges most or all of the time and running Squid in a chroot jail constitute the bulk of Squid's built-in security features. But, these are not the only things you can do to use Squid to enhance your network and end-user systems' security.
Next time, I'll show you how to use add-on tools such as SquidGuard to increase Squid's intelligence in how it evaluates clients' requests and servers' replies. I'll also address (if not next time then in a subsequent column) some of the finer points of proxying TLS/SSL-encrypted sessions. Until then, be safe!
Wessels, Duane: Squid: The Definitive Guide. Sebastopol, CA: O'Reilly Media, 2004. Includes some tips on creating and using a Squid chroot jail.
The Squid home page, where you can obtain the latest source code and binaries for Squid: www.squid-cache.org.
The Ubuntu Server Guide's Squid chapter: https://help.ubuntu.com/8.10/serverguide/C/squid.html.
The Squid User's Guide: www.deckle.co.za/squid-users-guide/Main_Page.
ViSolve's Squid 2.6 Configuration Manual and Comprehensive squid.conf Reference: www.visolve.com/squid/squid26/contents.php.
“The Homeless Hacker v. The New York Times”, Jennifer Kahn's article in Wired about Adrian Lamos: www.wired.com/wired/archive/12.04/hacker_pr.html.
Chris Wichura's slideshow “The Squid Caching Proxy”: www.uniforum.chi.il.us/slides/squid/UniForum-Squid.ppt.
Vivek Gite's tutorial “Howto: Squid proxy authentication using ncsa_auth helper”: www.cyberciti.biz/tips/linux-unix-squid-proxy-server-authentication.html.
Vivek Gite's Tutorial “Configure squid for LDAP authentication using squid_ldap_auth helper”: www.cyberciti.biz/tips/howto-configure-squid-ldap-authentication.html.
David Bolton's “Howto: Squid + msnt_auth + Active Directory”: www.davidbolton.com/?p=32.
Paul Matthews' HOWTO “Squid with PAM Authentication and Squish Download Manager”: www.opensourcehowto.org/how-to/squid/squid-with-pam-authentication--squish-download-manager.html.
Thread from the squid-users mailing list, on what should go into a Squid chroot jail: www.squid-cache.org/mail-archive/squid-users/200609/0782.html.
Thread from the squid-users mailing list, about some of the finer points of running Squid in a chroot jail: www.squid-cache.org/mail-archive/squid-users/200811/0411.html.
Mick Bauer (firstname.lastname@example.org) is Network Security Architect for one of the US's largest banks. He is the author of the O'Reilly book Linux Server Security, 2nd edition (formerly called Building Secure Servers With Linux), an occasional presenter at information security conferences and composer of the “Network Engineering Polka”.
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