-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= pfSense-SA-20_02.webgui Security Advisory pfSense Topic: XSS vulnerability in the WebGUI Category: pfSense Base System Module: webgui Announced: 2020-01-17 Credits: Catatonic Prime CVE ID: CVE-2019-12462 Affects: pfSense software versions <= 2.4.4-p3 Corrected: 2019-06-13 17:09:36 UTC (pfSense/master, pfSense 2.5.0) 2019-06-13 17:09:36 UTC (pfSense/RELENG_2_4_5, pfSense 2.4.5) 0. Revision History v1.0 2020-01-17 Initial SA draft I. Background pfSense® software is a free network firewall distribution based on the FreeBSD operating system. The pfSense software distribution includes third- party free software packages for additional functionality, and provides most of the functionality of common commercial firewalls. The majority of users of pfSense software have never installed or used a stock FreeBSD system. Unlike similar GNU/Linux-based firewall distributions, there is no need for any UNIX knowledge. The command line is never used, and there is no need to ever manually edit any rule sets. Instead, pfSense software includes a web interface for the configuration of all included components. Users familiar with commercial firewalls will quickly understand the web interface, while those unfamiliar with commercial-grade firewalls may encounter a short learning curve. II. Problem Description A Cross-Site Scripting (XSS) vulnerability was found in services_acb.php, a component of the pfSense software WebGUI, on version 2.4.4-p3 and earlier. The page did not encode the hostname parameter used with legacy settings in its output, leading to a possible XSS. III. Impact Due to the lack of proper encoding on the affected parameters susceptible to XSS, arbitrary JavaScript could be executed in the user's browser. The user's session cookie or other information from the session may be compromised. IV. Workaround Disable Legacy settings in AutoConfigBackup. The legacy backend has been deprecated and removed, so there is no benefit to retaining its settings. To help mitigate the problem on older releases, use one or more of the following: * Do not give firewall administrators access to pages or functions which allow writing arbitrary files to the firewall. * Limit access to the affected pages to trusted administrators only. * Do not log into the firewall with the same browser used for non- administrative web browsing. V. Solution Users can upgrade to version 2.4.5 or later. This upgrade may be performed in the web interface or from the console. See https://docs.netgate.com/pfsense/en/latest/install/upgrade-guide.html Users may also apply the relevant revisions below using the System Patches package on pfSense 2.4.4-p3. See https://docs.netgate.com/pfsense/en/latest/development/system-patches.html VI. Correction details The following list contains the correction revision commit ID for each affected item. Branch/path Revision - - ------------------------------------------------------------------------- pfSense/master fe482ccc1eaf59137b29008bc040faaad25088f0 pfSense/RELENG_2_4_5 9357ffe380b5eb5280ad58a596d7eb41963c58e6 - - ------------------------------------------------------------------------- VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE40XvjEU56XSUPIMdE7mH/ZIU+NoFAl4l9OcACgkQE7mH/ZIU +Np5lw/+N0sQ4CrL+clv3Q312/HmZQJUBb9Ga7GBmzJCR6/+ANKAR1/3pMVHg1tz CR4lrwJdo/FIW5Y6UqEXiO/+brdWCwdFW0XnqZ3D1pqvvBcb6VNllkKwXhUSfszi MMBUDgchw9+bvGFA7HXc7o4vm1osal79ydFsOekDxdiU3RdJgDn43PTFVnQmZx6b 7OArnaKxDhIKxWycc3xeoJSUi/ZA+j9NiK3K1gcFwD8VsD8KV24/ABTkrRuTTOKC SVWDewGrO+pXsY/gwhq23mSlzGFprzbsvHit9L1OrW4GEUrkILHrQpxwag+dk4Z9 Qwi5LQPP+yR59GzhtsWqO7QKJKDVxxTdC9AfiyVDRuWpZEOMtmMO/UvhYaj82KZy YygsGRQwQ68yUlx+ZxAQswPKxc/54jiYnGDrBn/WHWVlH9pN+t+fw2AW4L6a8Kcr 31P9K3Szl+Xt8DRPIBS0AmUO1VuuPbGc5jGI81lp1rOAmq3cl9hMghtXXGge/UjK pSSpnyoomGWN21lupwZX17Xk/3kAIqtErGzDafBKNDx0IvqVZa9qzI71nz7OiL8F sCGITFkqHgajGn122rjDIu0V3C/ajsAiMKmjBC3CV4ada7DcqMMPo2n/rqbMrhs1 3daY8r4Ke+vFAmdLV9HNniWw2sVgxJhZmjvtJlOYHugZ6fwYyFg= =ihRJ -----END PGP SIGNATURE-----