Fragmented Android development creating greater security risks

Some flaws exist on over a ‘hundred phone models and affect millions of users’

The fragmentation of Android is creating additional security risks, as the rush to release new devices without sufficient testing is inadvertently introducing security flaws, security researchers have warned.

The researchers – Xiaoyong Zhou, Yeonjoon Lee, Nan Zhang, Muhammad Naveed and XiaoFeng Wang – uncovered flaws in customised drivers using a custom tool, dubbed Addicted, that they developed as part of the study into what they argue is an overlooked problem.

"Running ADDICTED on popular phone models, we discovered critical flaws that allow an unauthorized app to take pictures and screenshots, and even record the user’s input keys from touchscreen," the researchers (computer scientists from Indiana University, Bloomington and University of Illinois at Urbana-Champaign) warn. "Those vulnerabilities were found to exist on hundreds of other phone models."

An abstract of their paper, entitled The Peril of Fragmentation: Security Hazards in Android Device Driver Customizations (pdf), explains:

Android phone manufacturers are under the perpetual pressure to move quickly on their new models, continuously customising Android to fit their hardware.

However, the security implications of this practice are less known, particularly when it comes to the changes made to Android’s Linux device drivers, such as those for camera, GPS, NFC etc.

In this paper, we report the first study aimed at a better understanding of the security risks in this customisation process. Our study is based on ADDICTED, a new tool we built for automatically detecting some types of flaws in customised driver protection.

Specifically, on a customised phone, ADDICTED performs dynamic analysis to correlate the operations on a security-sensitive device to its related Linux files, and then determines whether those files are under-protected on the Linux layer by comparing them with their counterparts on an official Android OS.

In this way, we can detect a set of likely security flaws on the phone. Using the tool, we analyzed three popular phones from Samsung, identified their likely flaws and built end-to-end attacks that allow an unprivileged app to take pictures and screenshots, and even log the keys the user enters through touchscreen.

Some of those flaws are found to exist on over a hundred phone models and affect millions of users.

We reported the flaws and helped the manufacturers fix those problems. We further studied the security settings of device files on 2423 factory images from major phone manufacturers, discovered over 1,000 vulnerable images, and also gained insights about how they are distributed across different Android versions, carriers and countries.

Vendors and carriers are aggressively customising official OS versions to accommodate new hardware pieces and services, potentially undermining Android security protection in the process, the security researchers conclude.

More than 1,000 phone models distributed across different Android versions, carriers and countries are vulnerable for one reason or the other, the researchers argue.

Independent mobile security experts, such as Jon Sawyer from Applied Cyber Security, agree that Android customisation has the side effect of creating a greater security risk.

"AOSP [Android Open Source Project] code has had the most eyes on it, from Google, the SOC partners, the OEMs, the community. It is quite reviewed," Sawyer told El Reg. "Customised code only really has had eyes from it's OEM on it. Some are more reviewed, and better than others. Some appear as if the OEM doesn't even have anyone look at it."

"So yes, many bugs come from OEM customisations," Sawyer concluded.

The US computer scientist conclude that their research only "scratches the surface of the grand security challenges" that come with Android customisations. Their conclusions point towards further work that ought to be undertaken.

"Even on the Linux layer, still there are many device files we cannot interpret, not to mention detection of their security flaws," the researchers conclude.

"More importantly, further effort is expected to understand how to protect security-critical resources on different Android layers, and develop effective means to ensure that customized resources are still well guarded," they added.

The research (first presented in Oakland last year) has been picked up by other researchers and taken forward. For example, a talk by Ohad Bobrov and  Avi Bashan at the Black Hat conference in Vegas next month draws heavily on the research of Xiaoyong Zhou et al. The Black Hat talk, entitled CERTIFI-GATE Front-door access to pwning millions of Android is due to show how even devices running the latest version of Android OS (Lollipop) can be hijacked.

Demonstration of an exploit against a live device is promised. Both Bobrov and  Bashan worked for Lacoon Mobile Security before moving to Check Point.

El Reg approached Xiaoyong Zhou, who took time out to bring us up to speed on his work.

"We have reported all vulnerabilities to Samsung and Google, the report includes 69 phone models that contain vulnerabilities allow unauthorised apps to take screenshots, key logger and use the camera without user consent," Zhou explained.

"Samsung awarded us with a Samsung Note phone to show its acknowledgement. Samsung also fixed its flagship phone models since the report. In its new flagship phones such as S6, Note 4, we did not find similar vulnerabilities," he added.

Further comparative work into the security of different Android customisations by a mix of researchers from IC-UNICAMP and Samsung can be found here.

The researchers analysed five different distributions: Google Nexus 4, Google Nexus 5, Sony Z1, Samsung Galaxy S4 and Samsung Galaxy S5, all running OS versions 4.4.X (except for Samsung S4 running version 4.3).

"Our conclusions indicate that serious security issues such as expanded attack surface and poorer permission control grow sharply with the level of customisation," the team concluded in a short six-page paper submitted for the 8th ACM Conference on Security & Privacy in Wireless and Mobile Networks.

El Reg approached representatives of Samsung directly for comment on the research by Xiaoyong Zhou et al into Android customisation, which is more detailed than the short paper put forward by Samsung boffins, but we're yet to hear back from the smartphone manufacturer. ®

Similar topics

Other stories you might like

  • Florida's content-moderation law kept on ice, likely unconstitutional, court says
    So cool you're into free speech because that includes taking down misinformation

    While the US Supreme Court considers an emergency petition to reinstate a preliminary injunction against Texas' social media law HB 20, the US Eleventh Circuit Court of Appeals on Monday partially upheld a similar injunction against Florida's social media law, SB 7072.

    Both Florida and Texas last year passed laws that impose content moderation restrictions, editorial disclosure obligations, and user-data access requirements on large online social networks. The Republican governors of both states justified the laws by claiming that social media sites have been trying to censor conservative voices, an allegation that has not been supported by evidence.

    Multiple studies addressing this issue say right-wing folk aren't being censored. They have found that social media sites try to take down or block misinformation, which researchers say is more common from right-leaning sources.

    Continue reading
  • US-APAC trade deal leaves out Taiwan, military defense not ruled out
    All fun and games until the chip factories are in the crosshairs

    US President Joe Biden has heralded an Indo-Pacific trade deal signed by several nations that do not include Taiwan. At the same time, Biden warned China that America would help defend Taiwan from attack; it is home to a critical slice of the global chip industry, after all. 

    The agreement, known as the Indo-Pacific Economic Framework (IPEF), is still in its infancy, with today's announcement enabling the United States and the other 12 participating countries to begin negotiating "rules of the road that ensure [US businesses] can compete in the Indo-Pacific," the White House said. 

    Along with America, other IPEF signatories are Australia, Brunei, India, Indonesia, Japan, South Korea, Malaysia, New Zealand, the Philippines, Singapore, Thailand and Vietnam. Combined, the White House said, the 13 countries participating in the IPEF make up 40 percent of the global economy. 

    Continue reading
  • 381,000-plus Kubernetes API servers 'exposed to internet'
    Firewall isn't a made-up word from the Hackers movie, people

    A large number of servers running the Kubernetes API have been left exposed to the internet, which is not great: they're potentially vulnerable to abuse.

    Nonprofit security organization The Shadowserver Foundation recently scanned 454,729 systems hosting the popular open-source platform for managing and orchestrating containers, finding that more than 381,645 – or about 84 percent – are accessible via the internet to varying degrees thus providing a cracked door into a corporate network.

    "While this does not mean that these instances are fully open or vulnerable to an attack, it is likely that this level of access was not intended and these instances are an unnecessarily exposed attack surface," Shadowserver's team stressed in a write-up. "They also allow for information leakage on version and build."

    Continue reading
  • A peek into Gigabyte's GPU Arm for AI, HPC shops
    High-performance platform choices are going beyond the ubiquitous x86 standard

    Arm-based servers continue to gain momentum with Gigabyte Technology introducing a system based on Ampere's Altra processors paired with Nvidia A100 GPUs, aimed at demanding workloads such as AI training and high-performance compute (HPC) applications.

    The G492-PD0 runs either an Ampere Altra or Altra Max processor, the latter delivering 128 64-bit cores that are compatible with the Armv8.2 architecture.

    It supports 16 DDR4 DIMM slots, which would be enough space for up to 4TB of memory if all slots were filled with 256GB memory modules. The chassis also has space for no fewer than eight Nvidia A100 GPUs, which would make for a costly but very powerful system for those workloads that benefit from GPU acceleration.

    Continue reading
  • GitLab version 15 goes big on visibility and observability
    GitOps fans can take a spin on the free tier for pull-based deployment

    One-stop DevOps shop GitLab has announced version 15 of its platform, hot on the heels of pull-based GitOps turning up on the platform's free tier.

    Version 15.0 marks the arrival of GitLab's next major iteration and attention this time around has turned to visibility and observability – hardly surprising considering the acquisition of OpsTrace as 2021 drew to a close, as well as workflow automation, security and compliance.

    GitLab puts out monthly releases –  hitting 15.1 on June 22 –  and we spoke to the company's senior director of Product, Kenny Johnston, at the recent Kubecon EU event, about what will be added to version 15 as time goes by. During a chat with the company's senior director of Product, Kenny Johnston, at the recent Kubecon EU event, The Register was told that this was more where dollars were being invested into the product.

    Continue reading
  • To multicloud, or not: Former PayPal head of engineering weighs in
    Not everyone needs it, but those who do need to consider 3 things, says Asim Razzaq

    The push is on to get every enterprise thinking they're missing out on the next big thing if they don't adopt a multicloud strategy.

    That shove in the multicloud direction appears to be working. More than 75 percent of businesses are now using multiple cloud providers, according to Gartner. That includes some big companies, like Boeing, which recently chose to spread its bets across AWS, Google Cloud and Azure as it continues to eliminate old legacy systems. 

    There are plenty of reasons to choose to go with multiple cloud providers, but Asim Razzaq, CEO and founder at cloud cost management company Yotascale, told The Register that choosing whether or not to invest in a multicloud architecture all comes down to three things: How many different compute needs a business has, budget, and the need for redundancy. 

    Continue reading

Biting the hand that feeds IT © 1998–2022