Vulnerabilities

An issue was discovered in KaiOS 3.0 before 3.1. The /system/bin/tctweb_server binary exposes a local web server that responds to GET and POST requests on port 2929. The server accepts arbitrary Bash commands and executes them as root. Because it is not permission or context restricted and returns proper CORS headers, it's accessible to all websites via the browser. At a bare minimum, this allows an attacker to retrieve a list of the user's installed apps, notifications, and downloads. It also allows an attacker to delete local files and modify system properties including the boolean persist.moz.killswitch property (which would render the device inoperable). This vulnerability is partially mitigated by SELinux which prevents reads, writes, or modifications to files or permissions within protected partitions.

An issue was discovered in KaiOS 3.0. The pre-installed Communications application exposes a Web Activity that returns the user's call log without origin or permission checks. An attacker can inject a JavaScript payload that runs in a browser or app without user interaction or consent. This allows an attacker to send the user's call logs to a remote server via XMLHttpRequest or Fetch.

An issue was discovered in KaiOS 2.5 and 2.5.1. The pre-installed File Manager application is vulnerable to HTML and JavaScript injection attacks. An attacker can send a file via email to the victim that will inject HTML into the File Manager application (assuming the victim chooses to download the email attachment). At a bare minimum, this allows an attacker to take control over the File Manager application's UI (e.g., display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application) and also allows an attacker to abuse any of the privileges available to the mobile application.

A Denial of Service issue has been discovered in the Gecko component of KaiOS 2.5 10.05 (platform 48.0.a2) on Nokia 8810 4G devices. When a crafted web page is visited with the internal browser, the Gecko process crashes with a segfault. Successful exploitation could lead to the remote code execution on the device.