NewLine Character Cause DoS: Folder & File Deletion Flaw

Discover how a subtle flaw in ExampleHub, a pivotal platform for collaborative data management, has exposed users to a security risk. This vulnerability allows attackers to disrupt essential file and folder management operations by leveraging special characters in file names. By inserting %0a, a newline character, attackers can trigger denial-of-service (DoS) scenarios, impacting data integrity and user workflow.

Understanding the Target:

ExampleHub is a collaborative platform that facilitates efficient data management and sharing. It is widely used by organizations for its robust features, which streamline workflow processes and enhance team collaboration. However, the discovery of a vulnerability that interferes with basic file and folder operations could have far-reaching implications for its users.

The Flaw in the System:

The vulnerability revolves around the system’s handling of file names that contain special characters, specifically %0a, which represents a newline character. When such a file is introduced into the system and shared or added to a folder, it disrupts the normal processing of file and folder management functions. The system interprets the %0a as a command delimiter, causing it to terminate the command prematurely, which prevents the successful deletion of the file or folder.

Steps to Reproduce:

To demonstrate this vulnerability, follow these steps:

Log in to ExampleHub and create a file named %0a.Share this file with another user or place it in a folder that is accessible to other users on the platform.Have the victim user add the file to their folder to simulate a typical file management scenario.The victim user tries to delete the folder containing the file or the file itself.Due to the %0a in the file name, the system fails to process the deletion correctly, causing the user to be unable to delete the file or manage the folder as intended.

Impact:

Data Integrity: The presence of files with special characters disrupts standard data management operations, potentially leading to data integrity issues.

Denial of Service (DoS): Users are prevented from deleting folders or files that contain %0a in their names, which can significantly hinder their workflow. This misinterpretation of the line feed as a command terminator effectively creates a denial-of-service condition for the affected operations.

Resolution and Bounty:

The vulnerability was promptly reported to ExampleHub’s security team, which led to a resolution. The team acknowledged the severity of the issue and awarded a bounty of $150 for the finding. Although the severity was initially marked as medium, it was later downgraded to low due to specific implementation nuances.

Takeaway:

This case underscores the importance of meticulous file name handling in software development. Even seemingly innocuous characters like %0a can cause significant disruptions if not managed correctly. As security researchers and developers, it is crucial to remain vigilant and ensure that all input is properly sanitized to prevent such vulnerabilities.