Entries Tagged "operating systems"

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xHelper Malware for Android

xHelper is not interesting because of its infection mechanism; the user has to side-load an app onto his phone. It’s not interesting because of its payload; it seems to do nothing more than show unwanted ads. it’s interesting because of its persistence:

Furthermore, even if users spot the xHelper service in the Android operating system’s Apps section, removing it doesn’t work, as the trojan reinstalls itself every time, even after users perform a factory reset of the entire device.

How xHelper survives factory resets is still a mystery; however, both Malwarebytes and Symantec said xHelper doesn’t tamper with system services system apps. In addition, Symantec also said that it was “unlikely that Xhelper comes preinstalled on devices.”

In some cases, users said that even when they removed the xHelper service and then disabled the “Install apps from unknown sources” option, the setting kept turning itself back on, and the device was reinfected in a matter of minutes after being cleaned.

From Symantec:

We first began seeing Xhelper apps in March 2019. Back then, the malware’s code was relatively simple, and its main function was visiting advertisement pages for monetization purposes. The code has changed over time. Initially, the malware’s ability to connect to a C&C server was written directly into the malware itself, but later this functionality was moved to an encrypted payload, in an attempt to evade signature detection. Some older variants included empty classes that were not implemented at the time, but the functionality is now fully enabled. As described previously, Xhelper’s functionality has expanded drastically in recent times.

We strongly believe that the malware’s source code is still a work in progress.

It’s a weird piece of malware. That level of persistence speaks to a nation-state actor. The continuous evolution of the malware implies an organized actor. But sending unwanted ads is far too noisy for any serious use. And the infection mechanism is pretty random. I just don’t know.

Posted on November 8, 2019 at 6:10 AMView Comments

Chinese Military Wants to Develop Custom OS

Citing security concerns, the Chinese military wants to replace Windows with its own custom operating system:

Thanks to the Snowden, Shadow Brokers, and Vault7 leaks, Beijing officials are well aware of the US’ hefty arsenal of hacking tools, available for anything from smart TVs to Linux servers, and from routers to common desktop operating systems, such as Windows and Mac.

Since these leaks have revealed that the US can hack into almost anything, the Chinese government’s plan is to adopt a “security by obscurity” approach and run a custom operating system that will make it harder for foreign threat actors — mainly the US — to spy on Chinese military operations.

It’s unclear exactly how custom this new OS will be. It could be a Linux variant, like North Korea’s Red Star OS. Or it could be something completely new. Normally, I would be highly skeptical of a country being able to write and field its own custom operating system, but China is one of the few that is large enough to actually be able to do it. So I’m just moderately skeptical.

EDITED TO ADD (6/12): Russia also wants to develop its own flavor of Linux.

Posted on June 6, 2019 at 7:04 AMView Comments

New Variants of Cold-Boot Attack

If someone has physical access to your locked — but still running — computer, they can probably break the hard drive’s encryption. This is a “cold boot” attack, and one we thought solved. We have not:

To carry out the attack, the F-Secure researchers first sought a way to defeat the the industry-standard cold boot mitigation. The protection works by creating a simple check between an operating system and a computer’s firmware, the fundamental code that coordinates hardware and software for things like initiating booting. The operating system sets a sort of flag or marker indicating that it has secret data stored in its memory, and when the computer boots up, its firmware checks for the flag. If the computer shuts down normally, the operating system wipes the data and the flag with it. But if the firmware detects the flag during the boot process, it takes over the responsibility of wiping the memory before anything else can happen.

Looking at this arrangement, the researchers realized a problem. If they physically opened a computer and directly connected to the chip that runs the firmware and the flag, they could interact with it and clear the flag. This would make the computer think it shut down correctly and that the operating system wiped the memory, because the flag was gone, when actually potentially sensitive data was still there.

So the researchers designed a relatively simple microcontroller and program that can connect to the chip the firmware is on and manipulate the flag. From there, an attacker could move ahead with a standard cold boot attack. Though any number of things could be stored in memory when a computer is idle, Segerdahl notes that an attacker can be sure the device’s decryption keys will be among them if she is staring down a computer’s login screen, which is waiting to check any inputs against the correct ones.

Posted on September 24, 2018 at 6:52 AMView Comments

Secure Speculative Execution

We’re starting to see research into designing speculative execution systems that avoid Spectre- and Meltdown-like security problems. Here’s one.

I don’t know if this particular design is secure. My guess is that we’re going to see several iterations of design and attack before we settle on something that works. But it’s good to see the research results emerge.

News article.

Posted on June 25, 2018 at 5:00 AMView Comments

New iPhone OS May Include Device-Unlocking Security

iOS 12, the next release of Apple’s iPhone operating system, may include features to prevent someone from unlocking your phone without your permission:

The feature essentially forces users to unlock the iPhone with the passcode when connecting it to a USB accessory everytime the phone has not been unlocked for one hour. That includes the iPhone unlocking devices that companies such as Cellebrite or GrayShift make, which police departments all over the world use to hack into seized iPhones.

“That pretty much kills [GrayShift’s product] GrayKey and Cellebrite,” Ryan Duff, a security researcher who has studied iPhone and is Director of Cyber Solutions at Point3 Security, told Motherboard in an online chat. “If it actually does what it says and doesn’t let ANY type of data connection happen until it’s unlocked, then yes. You can’t exploit the device if you can’t communicate with it.”

This is part of a bunch of security enhancements in iOS 12:

Other enhancements include tools for generating strong passwords, storing them in the iCloud keychain, and automatically entering them into Safari and iOS apps across all of a user’s devices. Previously, standalone apps such as 1Password have done much the same thing. Now, Apple is integrating the functions directly into macOS and iOS. Apple also debuted new programming interfaces that allow users to more easily access passwords stored in third-party password managers directly from the QuickType bar. The company also announced a new feature that will flag reused passwords, an interface that autofills one-time passwords provided by authentication apps, and a mechanism for sharing passwords among nearby iOS devices, Macs, and Apple TVs.

A separate privacy enhancement is designed to prevent websites from tracking people when using Safari. It’s specifically designed to prevent share buttons and comment code on webpages from tracking people’s movements across the Web without permission or from collecting a device’s unique settings such as fonts, in an attempt to fingerprint the device.

The last additions of note are new permission dialogues macOS Mojave will display before allowing apps to access a user’s camera or microphone. The permissions are designed to thwart malicious software that surreptitiously turns on these devices in an attempt to spy on users. The new protections will largely mimic those previously available only through standalone apps such as one called Oversight, developed by security researcher Patrick Wardle. Apple said similar dialog permissions will protect the file system, mail database, message history, and backups.

Posted on June 12, 2018 at 6:23 AMView Comments

BlackBerry's Global Encryption Key

Last week, there was a big news story about the BlackBerry encryption key. The news was that all BlackBerry devices share a global encryption key, and that the Canadian RCMP has a copy of it. Stupid design, certainly, but it’s not news. As the Register points out, this has been repeatedly reported on since 2010.

And note that this only holds for individual users. If your organization uses a BlackBerry Enterprise Server (BES), you have your own unique key.

Posted on April 25, 2016 at 5:54 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.