Researchers at Trend Micro have identified a vulnerability related to the Android manifest file that can be exploited to cause devices to crash.
The Android manifest file, AndroidManifest.xml, can be found in every application’s root directory. The file contains essential information about the app, including the name of the Java package, a description of components, the permissions needed, and the processes that host components.
According to experts, a specially crafted manifest file can be used to make devices inoperable by getting them into a reboot loop.
The vulnerability has been successfully reproduced by Trend Micro on Android 4.4.4, Android Lollipop, and older versions of the operating system. Researchers have found two ways to exploit the flaw: by using long strings and memory allocation, and through .APK files and a specific intent filter.
“Some apps may contain huge strings in their .XML files, using document type definition (DTD) technology. When this string reference is assigned to some of the tags in AndroidManifest.xml (e.g., permission name, label, name of activity), the Package Parser will require memory to parse this .XML file. However, when it requires more memory than is available, the PackageParser will crash. This triggers a chain reaction wherein all the running services stops and the whole system consequently reboots once,” Trend Micro explained in a blog post.
“The second way involves .APK files and a specific intent-filter, which declares what a service or activity can do. An icon will be created in the launcher if the manifest file contains an activity definition with this specific intent-filter. If there are many activities defined with this intent-filter, the same number of icons will be created in the home page after installation. However, if this number is too large, the .APK file will trigger a loop of rebooting,” the company added.
For testing purposes, researchers have created an application with a manifest file that generated the creation of 100,000 icons on the homescreen. When such an app is installed, the device keeps rebooting until it runs out of power. The only way to repair the smartphone is to flash the ROM, but this isn’t a task that regular users can do.
Trend Micro says it has notified Google of this flaw, but it’s uncertain if the search engine giant plans on doing anything to address it.
This particular issue doesn’t pose a threat to users’ data, but there are some more dangerous Android vulnerabilities that have been actively exploited by cybercriminals. In late December, Trend Micro revealed that malicious actors had been exploiting a Same Origin Policy (SOP) bypass flaw disclosed in September to compromise Facebook accounts.