FreeBSD : php -- open_basedir Race Condition Vulnerability (edabe438-542f-11db-a5ae-00508d6a62df)

This script is Copyright (C) 2006-2014 Tenable Network Security, Inc.


Synopsis :

The remote FreeBSD host is missing one or more security-related
updates.

Description :

Stefan Esser reports :

PHP's open_basedir feature is meant to disallow scripts to access
files outside a set of configured base directories. The checks for
this are placed within PHP functions dealing with files before the
actual open call is performed.

Obviously there is a little span of time between the check and the
actual open call. During this time span the checked path could have
been altered and point to a file that is forbidden to be accessed due
to open_basedir restrictions.

Because the open_basedir restrictions often not call PHP functions but
3rd party library functions to actually open the file it is impossible
to close this time span in a general way. It would only be possible to
close it when PHP handles the actual opening on it's own.

While it seems hard to change the path during this little time span it
is very simple with the use of the symlink() function combined with a
little trick. PHP's symlink() function ensures that source and target
of the symlink operation are allowed by open_basedir restrictions (and
safe_mode). However it is possible to point a symlink to any file by
the use of mkdir(), unlink() and at least two symlinks.

See also :

http://www.hardened-php.net/advisory_082006.132.html
http://www.nessus.org/u?6b29a622

Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 6.2
(CVSS2#AV:L/AC:H/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 5.9
(CVSS2#E:F/RL:U/RC:ND)
Public Exploit Available : true

Family: FreeBSD Local Security Checks

Nessus Plugin ID: 22504 (freebsd_pkg_edabe438542f11dba5ae00508d6a62df.nasl)

Bugtraq ID: 20326

CVE ID: CVE-2006-5178

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