Executive Summary

• On September 19, WeChat (a division of China Internet giant Tencent) posted a blog entry regarding a security flaw caused by external malware called XcodeGhost that was present in WeChat version 6.2.5 for iOS devices. The malware recorded user data and uploaded it to external servers. WeChat version 6.2.6, which was released on September 11, 2015, is the most recent version of the app and is not affected by the malware.
• WeChat had 600 million users worldwide as of the second quarter of 2015. Over this past weekend, many companies subsequently updated their apps, and Apple removed the affected apps from its online store.