(Credit: Apple)

Here is a synopsis of the 46 iPhone security vulnerabilities addressed by the latest operating-system update for the iPhone and iPod Touch. As may be expected, many of these security patches focus on the Web-browsing framework WebKit.

CoreGraphics Changes to CoreGraphics prevent maliciously crafted image and PDF files from causing unexpected application termination or arbitrary code execution; vulnerabilities causing the same problems in FreeType v2.3.8 were also patched.

Exchange Changes were made to prevent a user from connecting to a malicious Exchange server that could lead to the disclosure of sensitive information by adding improvements to the handling of untrusted certificate exceptions.

ImageIO Changes to ImageIO prevent the use of maliciously crafted PNG images from causing unexpected application termination or arbitrary code execution.

International Components for Unicode Changes to Unicode prevent the use of maliciously crafted content that may bypass Web site filters and result in cross-site scripting.

IPSec Changes to IPSec patch multiple vulnerabilities in the racoon daemon that may lead to a denial-of-service attack.

Libxml Changes to XML library Libxml patch multiple vulnerabilities in Libxml2 version 2.6.16.

Mail Changes were made to the Mail app to give users control over the loading of remote images in HTML messages (see below). Additionally, the app was changed to prevent an application from causing an alert to appear that may be used to initiate a phone call without user interaction.

MPEG-4 Video Codec Changes to the MPEG-4 Video Codec will prevent the viewing of maliciously crafted MPEG-4 video files that may lead to an unexpected device reset.

Profiles Changes to Profiles will prohibit the installation of a configuration profile that may weaken the passcode policy defined by Exchange ActiveSync.

Safari Changes to Safari support the clearing of Safari's history via the Settings application, allowing prevention of disclosure of the search history to a person with physical access to the device. Now search history is actually removed. Additionally, if a user were to interact with a maliciously crafted Web site, a patch has been put in place to prevent unexpected action on another site such as "clickjacking."

Telephony Changes to Telephony address a problem in which a remote attacker may cause an unexpected device reset.

WebKit Changes to Web-browsing framework WebKit were very numerous in this release, given how popular the iPhone has become for Web use. They included many fixes to prevent arbitrary code or script execution, when visiting maliciously crafted Web sites. Some of these vulnerabilities could lead to app crashes and unexpected device resets, or the disclosure of sensitive information.