iPhone OS 3.1.3 deals with several security issues outlined below.
A buffer overflow exists in the handling of mp4 audio files. Playing a maliciously crafted mp4 audio file may lead to an unexpected application termination or arbitrary code execution. This issue is addressed through improved bounds checking.
A buffer underflow exists in ImageIO’s handling of TIFF images. Viewing a maliciously crafted TIFF image may lead to an unexpected application termination or arbitrary code execution. This issue is addressed through improved bounds checking.
A memory corruption issue exists in the handling of a certain USB control message. A person with physical access to the device could use this to bypass the passcode and access the user’s data. This issue is addressed through improved handling of the USB control message.
Multiple input validation issues exist in WebKit’s handling of FTP directory listings. Accessing a maliciously crafted FTP server may lead to information disclosure, unexpected application termination, or execution of arbitrary code. This update addresses the issues through improved parsing of FTP directory listings.
When WebKit encounters an HTML 5 Media Element pointing to an external resource, it does not issue a resource load callback to determine if the resource should be loaded. This may result in undesired requests to remote servers. As an example, the sender of an HTML-formatted email message could use this to determine that the message was read. This issue is addressed by generating resource load callbacks when WebKit encounters an HTML 5 Media Element.