Description

Improper neutralization of special elements used in an OS command ('OS command injection') vulnerability in Digitální a informační agentura (DIA) eObčanka-Identifikace on MacOS enables an attacker to register a custom URL scheme (czeeopauth://) for parameterized application execution. Prior to version 3.6.0, incoming URL parameters were passed to the compiled AppleScript wrapper using concatenation without sufficient sanitization.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.3",
  "pubDate": "2026-08-31T15:17:35.980Z",
  "pubdate": "2026-08-31T15:17:35.980Z",
  "executiveSummary": "This vulnerability is an OS command injection flaw identified in the eObčanka-Identifikace application for MacOS, categorized under CWE-78: Improper Neutralization of Special Elements Used in an OS Command.\nThe flaw stems from the insecure handling of parameters within a custom URL scheme (czeeopauth://). By crafting a malicious URL, an unauthenticated local attacker can trigger the execution of arbitrary commands on the host operating system with the privileges of the application user.\nThe vulnerability affects eObčanka-Identifikace versions prior to 3.6.0. The primary impact involves potential full compromise of the user session, unauthorized execution of system-level operations, and possible data exfiltration.\nExploitation requires the attacker to entice a user to interact with a malicious link or to leverage another application capable of triggering the custom URL scheme. This vulnerability highlights the risks associated with improper IPC (Inter-Process Communication) and the unsafe use of AppleScript wrappers for handling external input.",
  "technicalDetails": "The root cause of this vulnerability is the insecure implementation of a custom URL scheme (czeeopauth://) handler, which facilitates inter-process communication between a web browser or external application and the eObčanka-Identifikace binary.\nIn affected versions (prior to 3.6.0), the application registers the czeeopauth:// protocol handler, allowing it to receive parameterized inputs from the operating system. Upon receiving a request, the application passes the provided URL parameters directly into a compiled AppleScript wrapper.\nThe vulnerability manifests through the use of string concatenation when constructing the command string for the AppleScript wrapper, rather than using sanitized, parameterized interfaces. By injecting shell metacharacters or AppleScript-specific delimiters into the URL parameters, an attacker can escape the intended command context.\nThe attack flow proceeds as follows: 1) The attacker constructs a malicious czeeopauth:// URL containing a payload designed to terminate the intended command and inject arbitrary commands (e.g., using command separators like ';' or '&'). 2) The attacker lures the victim to trigger this URL, either via a malicious website, an email link, or a separate compromised application on the same host. 3) The MacOS system identifies the registered URL scheme and launches the eObčanka-Identifikace application, passing the attacker-supplied payload as an argument. 4) The application, failing to sanitize the input, concatenates the malicious payload into the AppleScript execution string. 5) The AppleScript engine executes the injected commands, granting the attacker the privilege level of the logged-in user.\nBecause the AppleScript wrapper interacts directly with the system shell or OS execution environment, the attacker can execute arbitrary binaries or scripts available on the system. This leads to a total compromise of the application's runtime context, enabling post-exploitation activities such as installing persistent backdoors, modifying sensitive local files, or intercepting data processed by the application. This vulnerability does not require authentication or elevated privileges, as it leverages the trust the OS places in the registered protocol handler and the lack of input validation within the application’s binary."
}