Discovered by Tyler Bohan of Cisco Talos
Overview Talos is disclosing TALOS-2016-0262 (CVE-2017-2372) and TALOS-2017-0275 (CVE-2017-2374), an out of bounds write vulnerability in Apple GarageBand. GarageBand is a music creation program, allowing users to create and edit music easily and effectively from their Mac computer. GarageBand is installed by default on all Mac computers so there is a significant number of potential victims. This issue was partially resolved on 1/18/17 with a patch which addressed CVE-2017-2372, the patch released on 2/13/17 addressed CVE-2017-2374 resolving the issue.
This particular vulnerability is the result of the way the application parses the proprietary file format used for GarageBand files, .band. The format is broken into chunks with a specific length field for each. This length is controlled by the user and can be leveraged to expose an exploitable condition. This vulnerability could be exploited by a user opening a specially crafted .band file. The full details surrounding the vulnerability are available here and here.
The following Snort Rules will detect exploitation attempts. Note that additional rules may be released at a future date and current rules are subject to change pending additional vulnerability information. For the most current rule information, please refer to your FireSIGHT Management Center or Snort.org.
Snort Rules: 41350-41351