Overview
This blog post provides a comprehensive analysis of a recently discovered vulnerability, CVE-2025-52903, which affects the File Browser software. File Browser is a popular tool used for managing files within a specified directory. This critical vulnerability allows an attacker with the ‘Execute commands’ permission to perform arbitrary command execution, potentially leading to full system compromise or data leakage. The severity of this vulnerability underscores the importance of proper cybersecurity practices and the potential risks of not attending to software updates and patches promptly.
Vulnerability Summary
CVE ID: CVE-2025-52903
Severity: High (8.0)
Attack Vector: Network
Privileges Required: High (Execute commands permission)
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
File Browser | 2.32.0
How the Exploit Works
In version 2.32.0 of File Browser, a feature was introduced that allows the execution of shell commands predefined on a user-specific allowlist. However, the vulnerability arises due to the lack of validation of the executed commands, which makes it possible to execute arbitrary commands. Given the broad range of standard commands that allow the execution of subcommands, this vulnerability can be exploited by any user with the ‘Execute commands’ permission. Successful exploitation results in unrestricted code execution rights with the UID of the server process, potentially leading to complete system compromise or data leakage.
Conceptual Example Code
Here’s a conceptual example of how the vulnerability might be exploited:
# User logs in with 'Execute commands' permission
$ login -u user_with_execute_commands_permission
# User executes arbitrary command bypassing allowlist
$ execute_command 'rm -rf /*'In this example, the user is able to execute an arbitrary command (`rm -rf /*`) that deletes all files in the system, even though it’s not on the allowlist. The severity of the possible actions goes far beyond this example and could, in practice, lead to more nefarious outcomes such as installing malware or exfiltrating sensitive data.
Prevention and Mitigation
Until the bug is fixed, the maintainers recommend completely disabling the ‘Execute commands’ feature for all accounts. Furthermore, given that not all deployments require the command execution feature, it is suggested to operate File Browser from a distroless container image as a defense-in-depth measure.
A patch version has been issued to disable the feature for all existing installations, making it an opt-in feature and adding a warning in the documentation and on the console if the feature is enabled. It’s important to apply this vendor patch as soon as possible to mitigate potential system compromise or data leakage.
For immediate temporary mitigation, consider employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to monitor and block suspicious activities. However, this should not be considered a long-term solution as it doesn’t address the root cause of the vulnerability.
As always, it’s crucial to maintain a regular update and patch management routine to protect your systems against known vulnerabilities.