We’ve discovered a new family of iOS malware that successfully infected non-jailbroken devices we’ve named “AceDeceiver”.
What makes AceDeceiver different from previous iOS malware is that instead of abusing enterprise certificates as some iOS malware has over the past two years, AceDeceiver manages to install itself without any enterprise certificate at all. It does so by exploiting design flaws in Apple’s DRM mechanism, and even as Apple has removed AceDeceiver from App Store, it may still spread thanks to a novel attack vector.
AceDeceiver is the first iOS malware we’ve seen that abuses certain design flaws in Apple’s DRM protection mechanism — namely FairPlay — to install malicious apps on iOS devices regardless of whether they are jailbroken. This technique is called “FairPlay Man-In-The-Middle (MITM)” and has been used since 2013 to spread pirated iOS apps, but this is the first time we’ve seen it used to spread malware. (The FairPlay MITM attack technique was also presented at the USENIX Security Symposium in 2014; however, attacks using this technique are still occurring successfully.)
On March 4, we detected that the Transmission BitTorrent client installer for OS X was infected with ransomware, just a few hours after installers were initially posted. We have named this Ransomware “KeRanger.” The only previous ransomware for OS X we are aware of is FileCoder, discovered by Kaspersky Lab in 2014. As FileCoder was incomplete at the time of its discovery, we believe KeRanger is the first fully functional ransomware seen on the OS X platform.
Attackers infected two installers of Transmission version 2.90 with KeRanger on the morning of March 4. When we identified the issue, the infected DMG files were still available for downloading from the Transmission site (hxxps://download.transmissionbt.com/files/Transmission-2.90[.]dmg) Transmission is an open source project. It’s possible that Transmission’s official website was compromised and the files were replaced by re-compiled malicious versions, but we can’t confirm how this infection occurred.
Figure 1 KeRanger hosted in Transmission’s official website
The KeRanger application was signed with a valid Mac app development certificate; therefore, it was able to bypass Apple’s Gatekeeper protection. If a user installs the infected apps, an embedded executable file is run on the system. KeRanger then waits for for three days before connecting with command and control (C2) servers over the Tor anonymizer network. The malware then begins encrypting certain types of document and data files on the system. After completing the encryption process, KeRanger demands that victims pay one bitcoin (about $400) to a specific address to retrieve their files. Additionally, KeRanger appears to still be under active development and it seems the malware is also attempting to encrypt Time Machine backup files to prevent victims from recovering their back-up data.
Palo Alto Networks reported the ransomware issue to the Transmission Project and to Apple on March 4. Apple has since revoked the abused certificate and updated XProtect antivirus signature, and Transmission Project has removed the malicious installers from its website. Palo Alto Networks has also updated URL filtering and Threat Prevention to stop KeRanger from impacting systems. …Continue reading
Apple’s official iOS App Store is well known for its strict code review of any app submitted by a developer. This mandatory policy has become one of the most important mechanisms in the iOS security ecosystem to ensure the privacy and security of iOS users. But we recently identified an app that demonstrated new ways of successfully evading Apple’s code review. This post discusses our findings and potential security risks to iOS device users.
The app we identified is named “开心日常英语 (Happy Daily English),” and it has since been removed by Apple from the App Store. This app was a complex, fully functional third party App Store client for iOS users in mainland China. We also discovered enterprise signed versions of this application elsewhere in the wild. We had not identified any malicious functionality in this app, and as such we classified it as Riskware and have named it ZergHelper.
Figure 1: “Happy Daily English” available in the App Store
ZergHelper presents several security risks, include the following: …Continue reading