unhackable security

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.10
- Ubuntu 11.04
- Ubuntu 10.10
- Ubuntu 10.04 LTS
- Ubuntu 8.04 LTS

Summary:

USN 1358-1 introduced a regression in PHP.

Software Description:
- php5: HTML-embedded scripting language interpreter

Details:

USN 1358-1 fixed multiple vulnerabilities in PHP. The fix for
CVE-2012-0831 introduced a regression where the state of the
magic_quotes_gpc setting was not correctly reflected when calling
the ini_get() function.

Original advisory details:

It was discovered that PHP computed hash values for form parameters
without restricting the ability to trigger hash collisions predictably.
This could allow a remote attacker to cause a denial of service by
sending many crafted parameters. (CVE-2011-4885)

ATTENTION: this update changes previous PHP behavior by
limiting the number of external input variables to 1000.
This may be increased by adding a “max_input_vars”
directive to the php.ini configuration file. See

http://www.php.net/manual/en/info.configuration.php#ini.max-input-vars

for more information.

Stefan Esser discovered that the fix to address the predictable hash
collision issue, CVE-2011-4885, did not properly handle the situation
where the limit was reached. This could allow a remote attacker to
cause a denial of service or execute arbitrary code via a request
containing a large number of variables. (CVE-2012-0830)

It was discovered that PHP did not always check the return value of
the zend_strndup function. This could allow a remote attacker to
cause a denial of service. (CVE-2011-4153)

It was discovered that PHP did not properly enforce libxslt security
settings. This could allow a remote attacker to create arbitrary
files via a crafted XSLT stylesheet that uses the libxslt output
extension. (CVE-2012-0057)

It was discovered that PHP did not properly enforce that PDORow
objects could not be serialized and not be saved in a session. A
remote attacker could use this to cause a denial of service via an
application crash. (CVE-2012-0788)

It was discovered that PHP allowed the magic_quotes_gpc setting to
be disabled remotely. This could allow a remote attacker to bypass
restrictions that could prevent an SQL injection. (CVE-2012-0831)

USN 1126-1 addressed an issue where the /etc/cron.d/php5 cron job
for PHP allowed local users to delete arbitrary files via a symlink
attack on a directory under /var/lib/php5/. Emese Revfy discovered
that the fix had not been applied to PHP for Ubuntu 10.04 LTS. This
update corrects the issue. We apologize for the error. (CVE-2011-0441)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 11.10:
libapache2-mod-php5 5.3.6-13ubuntu3.6
php5 5.3.6-13ubuntu3.6
php5-cgi 5.3.6-13ubuntu3.6
php5-cli 5.3.6-13ubuntu3.6

Ubuntu 11.04:
libapache2-mod-php5 5.3.5-1ubuntu7.7
php5 5.3.5-1ubuntu7.7
php5-cgi 5.3.5-1ubuntu7.7
php5-cli 5.3.5-1ubuntu7.7

Ubuntu 10.10:
libapache2-mod-php5 5.3.3-1ubuntu9.10
php5 5.3.3-1ubuntu9.10
php5-cgi 5.3.3-1ubuntu9.10
php5-cli 5.3.3-1ubuntu9.10

Ubuntu 10.04 LTS:
libapache2-mod-php5 5.3.2-1ubuntu4.14
php5 5.3.2-1ubuntu4.14
php5-cgi 5.3.2-1ubuntu4.14
php5-cli 5.3.2-1ubuntu4.14

Ubuntu 8.04 LTS:
libapache2-mod-php5 5.2.4-2ubuntu5.23
php5 5.2.4-2ubuntu5.23
php5-cgi 5.2.4-2ubuntu5.23
php5-cli 5.2.4-2ubuntu5.23

In general, a standard system update will make all the necessary changes.

References:
http://www.ubuntu.com/usn/usn-1358-2
http://www.ubuntu.com/usn/usn-1358-1
https://launchpad.net/bugs/930115