$ sudo docker pull blabla1337/owasp-skf-lab:js-racecondition-file-write

$ sudo docker run -ti -p 127.0.0.1:5000:5000 blabla1337/owasp-skf-lab:js-racecondition-file-write

app.get("/:value", (req, res) => {
  fs.writeFileSync("shared-file.txt", req.params.value);
  fs.open("shared-file.txt", "r", (err, fd) => {
    let file = fs.readFileSync("shared-file.txt", "utf8");
    res.setHeader("Content-Type", "text/html", "charset=utf-8");
    res.setHeader(
      "Content-Disposition",
      "attachment; filename=shared-file.txt"
    );
    res.sendFile(__dirname + "/shared-file.txt");
  });
});

fs.writeFileSync("shared-file.txt", req.params.value);

fs.open("shared-file.txt", "r", (err, fd) => {
  let file = fs.readFileSync("shared-file.txt", "utf8");
  res.setHeader("Content-Type", "text/html", "charset=utf-8");
  res.setHeader("Content-Disposition", "attachment; filename=shared-file.txt");
  res.sendFile(__dirname + "/shared-file.txt");
});

#!/bin/bash

while true; do

	curl -i -s -k  -X $'GET' -H $'Host: localhost:5000' $'http://localhost:5000/111' | grep "111"

done

$ sudo docker pull blabla1337/owasp-skf-lab:racecondition-file-write

$ sudo docker run -ti -p 127.0.0.1:5000:5000 blabla1337/owasp-skf-lab:racecondition-file-write

@app.route("/<string:value>", methods=['GET'])
def home(value):
    # Create a Python file object using open() and the with statement
    with open("shared-file.txt", 'w') as f:
        f.write(value)
        f.closed
        f.closed
    file = open("shared-file.txt", "r")
    response = make_response(send_file("shared-file.txt", attachment_filename="shared-file.txt"))
    response.headers.set("Content-Type", "text/html; charset=utf-8")
    response.headers.set("Content-Disposition", "attachment; filename=shared-file.txt")
    return response

with open("shared-file.txt", 'w') as f:
        f.write(value)
        f.closed
        f.closed

 file = open("shared-file.txt", "r")
    response = make_response(send_file("shared-file.txt", attachment_filename="shared-file.txt"))
    response.headers.set("Content-Type", "text/html; charset=utf-8")
    response.headers.set("Content-Disposition", "attachment; filename=shared-file.txt")
    return response

#!/bin/bash

while true; do

	curl -i -s -k  -X $'GET' -H $'Host: localhost:5000' $'http://localhost:5000/111' | grep "111"

done

$ sudo docker pull blabla1337/owasp-skf-lab:java-racecondition-file-write

$ sudo docker run -ti -p 127.0.0.1:5000:5000 blabla1337/owasp-skf-lab:java-race-condition-file-write

public class RaceConditionController {
  @GetMapping("/{value}")
  public ResponseEntity<Object> downloadFile(@PathVariable String value, Model model) throws IOException {
    FileWriter fileWriter = new FileWriter("shared-file.txt", false);
    fileWriter.write(value);
    fileWriter.close();
    File file = new File("shared-file.txt");
    InputStreamResource resource = new InputStreamResource(new FileInputStream(file));
    HttpHeaders headers = new HttpHeaders();
    headers.add("Content-Disposition", String.format("attachment; filename=\"%s\"", file.getName()));
    headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
    headers.add("Pragma", "no-cache");
    headers.add("Expires", "0");
    ResponseEntity<Object> responseEntity = ResponseEntity.ok().headers(headers).contentLength(file.length())
        .contentType(
            MediaType.parseMediaType("application/txt"))
        .body(resource);

    return responseEntity;
  }
}

InputStreamResource resource = new InputStreamResource(new FileInputStream(file));

HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", String.format("attachment; filename=\"%s\"", file.getName()));
headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
headers.add("Pragma", "no-cache");
headers.add("Expires", "0");
ResponseEntity<Object> responseEntity = ResponseEntity.ok().headers(headers).contentLength(file.length())
    .contentType(MediaType.parseMediaType("application/txt"))
    .body(resource);
return responseEntity;

#!/bin/bash

while true; do

	curl -i -s -k  -X $'GET' -H $'Host: localhost:5000' $'http://localhost:5000/111' | grep "111"

done