Apple might have one of the most secure app stores on the planet, but as with all things secure, someone is bound to find a hole and waltz right on in. Such is the case with whomever modified Apple's official coding software Xcode to bundle malware with any app compiled with it. That sounds simple, but despite the origin being China, this malware is far-reaching.
According to security firm Palo Alto Networks, a malicious version of Xcode was released to Chinese networks about six months ago. While the software is free to registered developers, some users in China took advantage of this unofficial download for the sake of ease, and perhaps to achieve better download speeds. It's noted that unofficial versions between 6.1 and 6.4 are affected.
WeChat was an app infected with XcodeGhost malware
When developers compiled their apps with this malicious tool, it injected malware Palo Alto Networks dubs XcodeGhost. While it might seem like Apple would detect this kind of malware as it passes through its verification process, it didn't, which allowed these malware-laden apps to be downloaded by anyone.
At its website, Palo Alto Networks lists all of the infected software it could find. While most of it is Chinese, there are some apps that would have been downloaded quite frequently in the US. Some notable examples are CamCard, WinZip, and WeChat.
Once news broke of this malware, Apple was quick to purge all of the guilty apps from its store. Likewise, many developers who meant to do no wrong have recompiled and released updated versions of their apps.
If you happen to have installed an app that had this malware, simply uninstalling it or upgrading to the latest version should get rid of it. Past that, though, you'll definitely want to reset your iCloud password and any other passwords that you used while infected with this malware.