Malware Strikes iOS Devices

Tuesday, September 1, 2015 @ 05:09 PM gHale

Credentials for more than 225,000 Apple accounts ended up stolen by sophisticated malware that targets modified iOS devices, according to researchers at Palo Alto Networks.

The malware, called KeyRaider, enables attackers to download applications from Apple’s App Store without paying. It can also lock devices forcing victims to pay a ransom.

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“We believe this to be the largest known Apple account theft caused by malware,” said Claud Xiao of Palo Alto Networks in a blog post.

Palo Alto Networks notified Apple of the issue Aug. 26 and provided the stolen account information, Xiao said.

KeyRaider can infect only those who have “jailbroken” their Apple device. Jailbreaking removes Apple’s protections that limit what apps can end up installed on a device. Apple advises against jailbreaking for security reasons.

Palo Alto Networks investigated KeyRaider with an amateur technical group in China called WeipTech. A member of that group, who is a student at Yangzhou University, discovered the attack, Xiou said.

KeyRaider spread by being in jailbreak tweaks, or software packages that allow for some new function to run on iOS. The malware ended up found within tweaks published on the Weiphone forum for jailbroken phones.

Researchers suspect a user on Weiphone, mischa07, may be responsible for seeding KeyRaider to his personal repository of apps. The same user name ended up hardcoded into KeyRaider as the encryption and decryption key for the malware, Xiao said.

An analysis of mischa07’s repository showed the user uploaded tweaks to Weiphone, including ones that allow users to cheat on games, tune their systems and strip advertisements from apps.

KeyRaider taps into system processes within Cydia, which is the application used for downloading apps for jailbroken phones. It steals Apple account usernames, passwords and a device’s GUID by intercepting iTunes traffic, which it can then use to fraudulently download apps. The malware also collects certificates, private keys and purchase receipts.

In another style of attack, KeyRaider also ended up used for at least one ransomware attempt. The malware can “locally disable any kind of unlocking operations, whether the correct passcode or password has been entered,” Xiao said.

One victim reported a locked phone and showed a message to contact someone over the QQ instant messaging service.

The stolen account information ended up discovered by WeipTech on a command-and-control server that communicates with KeyRaider-infected phones. That server had security vulnerabilities which allowed the group to obtain the stolen data. But KeyRaider’s authors figured out something was going on.

WeipTech recovered only about half of the stolen accounts “before the attacker fixed the vulnerability,” Xiao said.