A malicious app campaign which infiltrated Apple’s App Store is far more extensive than at first thought, according to security researchers.
The original report from Palo Alto Networks five days ago claimed that 39 malicious apps had passed Apple’s strict vetting process to end up on its China App Store.
Even this small number was thought to potentially affect hundreds of millions of users as it included versions of popular software including messaging service WeChat.
However, FireEye said yesterday that the number of affected apps is actually closer to 4000.
The hackers managed to get malicious apps onto the App Store by producing a malicious version of Apple’s Xcode compiler software – XcodeGhost – which they promoted to developers via forums and the like.
The malware is said to steal user and device info and transmit it back to a C&C server. It was originally thought the attackers could then use the information to craft phishing attacks requesting iCloud passwords.
However, a new blog from Appthority suggests the author of this particular strain decided not to implement such “harmful behaviors.”
“The framework itself contains no code to display login prompts or alerts of any kind that could be used to phish credentials (the alert has no field for text input). The only way to launch a phishing attack using this framework would be to send the response to open a URL pointing to a malicious website,” Appthority said.
“The identified versions of XCodeGhost actually behaved more like adware or tracking frameworks rather than malicious malware, and we don’t see it as an immediate security threat.”
That said, FireEye warned that, while the XcodeGhost C&C server has now been taken down, the malicious apps are still trying to connect via HTTP.
As a result, this HTTP session is “vulnerable to hijacking by other attackers,” it claimed.