Mysterious malware steals Apple credentials from jailbroken iOS devices

Some iOS users found a malicious library of unknown origin on their jailbroken devices

A malware campaign of yet-to-be-determined origin is infecting jailbroken iPhones and iPads to steal Apple account credentials from SSL encrypted traffic.

The threat was discovered after some users reported on Reddit that they experienced crashes in some applications as a result of a mysterious MobileSubstrate add-on called Unflod.

MobileSubstrate, now called Cydia Substrate, is a framework for jailbroken devices that allows developers to create modifications for iOS.

"This 'substrate' allows you to extend and to modify the behaviour of iOS in ways that are deliberately prohibited by Apple on unjailbroken devices, such as by hooking, or intercepting, system functions to make them do new and interesting (though sadly also perhaps dangerous) things," wrote Paul Ducklin, the head of technology for Asia-Pacific at antivirus vendor Sophos, in a blog post Monday.

It appears that someone created a dynamic library for Cydia Substrate that hooks the legitimate iOS SSLWrite function to read data before it's encrypted and sent over a secure SSL connection. The rogue library is called Unflod.dylib, but instances with the name framework.dylib have also been observed.

"It has been suggested that the choice of name might have something to do with the existence of a real tweak called Unfold," researchers from SektionEins, a security consultancy company based in Germany, said in a blog post discussing the threat. "The choice of name might therefore just be an attempt to hide in plain sight."

After hooking the SSLWrite function, the malware monitors traffic for authentication requests with Apple's services. It then extracts Apple IDs and passwords from the data and sends them to one of two hardcoded IP (Internet Protocol) addresses.

It's not clear how the malicious Unflod.dylib library gets installed on jailbroken devices, but users and researchers have advanced the possibility that packages from unofficial repositories might be the source of infection.

There's also some circumstantial evidence pointing to a Chinese connection, the library being digitally signed with a legitimate developer certificate issued by Apple in February to someone named Wang Xin.

"This person might be a fake persona, the victim of certificate theft or really involved," the SektionEins researchers said. "It is impossible for us to know, but Apple should be able to investigate from this information and terminate that developer account."

However, whether the developer certificate is valid or not doesn't really matter, because the malicious code doesn't need to be digitally signed to work on jailbroken devices in the first place.

"Currently the jailbreak community believes that deleting the Unflod.dylib/framework.dylib binary and changing the Apple ID's password afterwards is enough to recover from this attack," the SektionEins researchers said.

"However it is still unknown how the dynamic library ends up on the device in the first place and therefore it is also unknown if it comes with additional malware gifts. We therefore believe that the only safe way of removal is a full restore, which means the removal and loss of the jailbreak," the researchers added.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags mobilemalwaremobile securityAppleiosapplicationstelecommunicationsophosspywareMobile OSesSektionEins

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Lucian Constantin

Lucian Constantin

IDG News Service
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?