Description

SiYuan File Read API Case Sensitivity Bypass can Lead to Path Traversal

File Read Interface Case Bypass Vulnerability

Vulnerability Name

File Read Interface Case Bypass Vulnerability

Overview

The /api/file/getFile endpoint uses case-sensitive string equality checks to block access to sensitive files. On case-insensitive file systems such as Windows, attackers can bypass restrictions using mixed-case paths and read protected configuration files.

Impact

Read sensitive information in configuration files (e.g., access codes, API Tokens, sync configurations, etc.).

Remotely exploitable directly when the service is published without authentication.

Trigger Conditions

Running on a case-insensitive file system.

The caller can access /api/file/getFile (via CheckAuth or Token injection in published services).

PoC (Generic Example)

After enabling publication:

Request:

POST /api/file/getFile
Content-Type: application/json

{"path":"cOnf/conf.json"}

Expected Result:

Successfully return the content of the configuration file.

Root Cause

Path comparison uses strict case-sensitive string matching, without case normalization or identical file validation.

Fix Recommendations

Normalize path casing before comparison (Windows/macOS).

Use file-level comparison methods such as os.SameFile.

Apply blacklist validation on sensitive paths after case normalization.

Notes

Environment identifiers and sensitive information have been removed.

Solution Commit

399a38893e8719968ea2511e177bb53e09973fa6

Mitigation

Aliases

References