-----BEGIN PGP SIGNED MESSAGE----- ============================================================================= FreeBSD-SA-00:60 Security Advisory FreeBSD, Inc. Topic: boa web server allows arbitrary file access/execution Category: ports Module: boa Announced: 2000-10-30 Credits: Lluis Mora Affects: Ports collection prior to the correction date. Corrected: 2000-10-07 Vendor status: Updated version released FreeBSD only: NO I. Background Boa is a high-performance web server. II. Problem Description The boa port, versions after 0.92 but prior to 0.94.8.3, contains a vulnerability which allows remote users to view arbitrary files outside the document root. The vulnerability is that boa does not correctly restrict URL-encoded requests containing ".." in the path. In addition, if the administrator has enabled CGI extension support, a request for any file ending in .cgi will result in the file being executed with the privileges of the user id running the web server. Since the .cgi file may reside outside the document root, this may result in untrusted binaries/scripts being executed. If an attacker can upload files to the system, e.g. via anonymous FTP, they can cause arbitrary code to be executed by the user running the web server. The boa port is not installed by default, nor is it "part of FreeBSD" as such: it is part of the FreeBSD ports collection, which contains over 4000 third-party applications in a ready-to-install format. The ports collections shipped with FreeBSD 3.5.1 and 4.1.1 contain this problem since it was discovered after the releases. FreeBSD makes no claim about the security of these third-party applications, although an effort is underway to provide a security audit of the most security-critical ports. III. Impact Remote users may view any file on the system that is accessible by the webserver account. In addition, the webserver account may be compromised due to the execution of arbitrary files outside the document root. If you have not chosen to install the boa port/package, then your system is not vulnerable to this problem. IV. Workaround Deinstall the boa port/package, if you you have installed it. V. Solution One of the following: 1) Upgrade your entire ports collection and rebuild the boa port. 2) Deinstall the old package and install a new package dated after the correction date, obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/www/boa-0.94.8.3.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/www/boa-0.94.8.3.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/www/boa-0.94.8.3.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/www/boa-0.94.8.3.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/www/boa-0.94.8.3.tgz 3) download a new port skeleton for the cvsweb port from: http://www.freebsd.org/ports/ and use it to rebuild the port. 4) Use the portcheckout utility to automate option (3) above. The portcheckout port is available in /usr/ports/devel/portcheckout or the package can be obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.4 (FreeBSD) Comment: For info see http://www.gnupg.org iQCVAwUBOf3+LlUuHi5z0oilAQHuAAP+PB/Y6PwDyWZrfvX5cKRdnQiwebU2FPiS BhKSwjwBsE4jZGFw0YC+tU6TksGhun6LvvIw0DVHXRevH0VwPcf18akuqKQrFhPA r3NQ1atFvrdDoGQN0J4px1vANXKPu6afe1LKaMTeF+sbjokoniScnAFyH9IHBvQH mVUcDXhq7sU= =WmZ+ -----END PGP SIGNATURE-----