|
Brought to you by:
Suppliers of:
|
|
|
| |
A few security vulnerabilities have been found in the Boa web server. One of them allows reading of files outside the confines of the document root directory; another allows to execute CGIs that are found in arbitrary directories (even ones that has been uploaded by an attacker). For more information about the vulnerabilities see: BOA web server vulnerable to web path traversal (%2E replacement).
Boa has now released a patch that deals with these problems. |
| |
Credit:
The information has been provided by Lluis Mora and FreeBSD Security Advisories.
|
| |
Vulnerable systems:
Boa web server versions 0.92 to 0.94.8.3 (excluding 0.94.8.3)
Immune systems:
Boa web server version 0.94.8.3
The boa port, versions after 0.92 but prior to 0.94.8.3, suffers from a vulnerability that 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.
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.
Workaround:
Uninstall the boa port/package, if you have installed it.
Solution:
One of the following:
1) Upgrade your entire ports collection and rebuild the boa port.
2) Uninstall 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
|
|
|
|
|
