There is an important Debian update for PHP today to fix a number of vulnerabilities such as regression and buffer overflows. The crypt_blowfish function also had a bug that did not properly handle 8-bit characters, which could lead to passwords being cracked easier. This is one of the larger security fixes for PHP in the past year, so you should update your PHP package immediately.
Package : php5
Vulnerability : several
Problem type : remote
CVE ID : CVE-2011-1938 CVE-2011-2483 CVE-2011-4566 CVE-2011-4885
A regression was found in the fix for PHP’s XSLT transformations (CVE-2012-0057). Updated packages are now available to address this regression. For reference, the original advisory text follows.
Several vulnerabilities have been discovered in PHP, the web scripting language. The Common Vulnerabilities and Exposures project identifies the following issues:
The UNIX socket handling allowed attackers to trigger a buffer overflow
via a long path name.
The crypt_blowfish function did not properly handle 8-bit characters,
which made it easier for attackers to determine a cleartext password
by using knowledge of a password hash.
When used on 32 bit platforms, the exif extension could be used to
trigger an integer overflow in the exif_process_IFD_TAG function
when processing a JPEG file.
It was possible to trigger hash collisions predictably when parsing
form parameters, which allows remote attackers to cause a denial of
service by sending many crafted parameters.
When applying a crafted XSLT transform, an attacker could write files
to arbitrary places in the filesystem.
NOTE: the fix for CVE-2011-2483 required changing the behaviour of this
function: it is now incompatible with some old (wrongly) generated hashes for passwords containing 8-bit characters. See the package NEWS entry for details. This change has not been applied to the Lenny version of PHP.
NOTE: at the time of release packages for some architectures are still being built. They will be installed into the archive as soon as they arrive.
For the oldstable distribution (lenny), these problems have been fixed in version 5.2.6.dfsg.1-1+lenny15.
For the stable distribution (squeeze), these problems have been fixed in version 5.3.3-7+squeeze6.
For the testing distribution (wheezy) and unstable distribution (sid), these problems have been fixed in version 5.3.9-1.
We recommend that you upgrade your php5 packages.
Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: http://www.debian.org/security/