ChronoRace is a tool to accurately perform timed race conditions to circumvent application business logic. I’ve found in my research that well timed race conditions can allow for uncovering all kinds of interesting edge cases. An example use case is seen here, where I was able to get arbitrary email confirmation by hitting both the confirmation and email change endpoints a couple hundred milliseconds apart.


ChronoRace takes in raw requests and repeats them with a specified time delay. Create files with the raw requests you want to run as done in the http_requests/example/ folder. Then create a configuration which references the requests.

Sample configuration

  "proxy": "",
  "verify_ssl": false,
  "requests": [
      "file": "http_requests/example/get.txt",
      "delay": 0,
      "replacements": []
      "file": "http_requests/example/post.txt",
      "delay": 500,
      "replacements": [
        ["[REPLACE]", "bar"]
Config Parameter Type Description Required Default
requests array Array of requests to make. Yes
requests[x].file string Path to file containing the raw http request. Yes
requests[x].delay integer Delay in milliseconds since start. No 0
requests[x].replacements array Replacements to perform in the request. [["replace1", "with1"], ["replace2", "with2"]]. No []
requests[x].secure boolean Make request using the https protocol. No true
proxy string Proxy URL. It’s recommended to send through Burp to track the requests. No null
verify_ssl boolean Skip certificate validation. No true
threads integer Maximum number of simultaneous requests. Less threads than requests will delay them. No 100
print_response boolean Print the entire response in the console. No false


pip install -r requirements.txt
python race -c config.json


View Github