Arp Spoofing in Axum

Arp Spoofing in Axum applications typically occurs when handling network requests that involve ARP table manipulation or when Axum servers are deployed in environments where ARP cache poisoning is possible. In Rust's Axum framework, this manifests most commonly in scenarios where:

• Middleware processes network-level information before routing decisions
• WebSocket connections are established without proper authentication
• API endpoints accept network configuration data that could be manipulated

A common vulnerable pattern in Axum applications involves middleware that trusts network-level information:

use axum::{routing::get, Router, Json};
use std::net::IpAddr;

async fn get_client_ip_stateful() -> Json<String> {
    // Vulnerable: trusts network info that could be spoofed via ARP poisoning
    let client_ip = /* some network extraction logic */;
    Json(format!("Your IP: {}", client_ip))
}

let app = Router::new()
    .route("/ip", get(get_client_ip_stateful));

The ARP spoofing risk in Axum becomes critical when the framework's async handlers process requests that influence network routing decisions or when Axum applications serve as gateways that could be manipulated through ARP cache poisoning attacks.

Detecting ARP spoofing vulnerabilities in Axum applications requires examining both the application code and the deployment environment. Using middleBrick's API security scanner, you can identify these issues through:

• Network Information Trust Analysis: Scans check if Axum handlers trust client-provided network information without validation
• Authentication Bypass Detection: Identifies endpoints that could be accessed through ARP manipulation
• WebSocket Security Assessment: Examines WebSocket handlers for proper authentication before connection establishment

middleBrick specifically tests Axum applications by sending requests that attempt to exploit ARP-related vulnerabilities:

$ middlebrick scan https://api.example.com

=== ARP Spoofing Detection ===
✅ Authentication Bypass: No unauthenticated endpoints found
⚠️  Network Trust Analysis: Middleware trusts client IP without validation
✅ WebSocket Security: All WebSocket endpoints require authentication

Security Score: B (85/100)
Recommendations: Implement IP validation middleware, add ARP detection mechanisms

For development environments, you can use network monitoring tools alongside Axum's logging to detect suspicious ARP activity patterns that might indicate an ongoing attack.

Securing Axum applications against ARP spoofing requires implementing defense-in-depth strategies. Here are Axum-specific remediation techniques:

1. Network Information Validation Middleware

use axum::{middleware::Next, Request, Json};
use std::net::IpAddr;

async fn validate_network_info(mut req: Request<B>, next: Next<'_, B>) -> Json<String> {
    // Validate client IP against trusted sources
    let client_ip = req.headers().get("x-forwarded-for")
        .and_then(|h| h.to_str().ok())
        .map(|s| s.split(',').next().unwrap().trim().to_string());
    
    // Only trust IPs from known subnets
    if let Some(ip) = client_ip {
        if !is_trusted_subnet(&ip) {
            return Json("Unauthorized network source".to_string());
        }
    }
    
    next.run(req).await
}

fn is_trusted_subnet(ip: &str) -> bool {
    // Implement your subnet validation logic
    true // placeholder
}

use axum_extra::ws::{Message, WebSocket, WebSocketUpgrade};
use async_trait::async_trait;

struct AuthenticatedWebSocket;

#[async_trait]
impl axum_extra::ws::OnUpgrade for AuthenticatedWebSocket {
    async fn on_upgrade(mut socket: WebSocket) {
        // Authenticate before allowing WebSocket operations
        if !authenticate_client(&socket) {
            return; // Close connection if authentication fails
        }
        
        while let Some(msg) = socket.recv().await {
            // Process messages only after authentication
        }
    }
}

async fn websocket_endpoint() -> WebSocketUpgrade {
    WebSocketUpgrade::on_upgrade(AuthenticatedWebSocket)
}

use axum::{routing::get, Router, Json};
use std::time::Duration;

async fn arp_spoofing_detection() -> Json<String> {
    // Check for ARP cache inconsistencies
    let arp_cache = get_arp_cache().await;
    let anomalies = detect_arp_anomalies(&arp_cache);
    
    if !anomalies.is_empty() {
        // Trigger alerts or defensive measures
        alert_arp_attack(&anomalies).await;
    }
    
    Json(format!("ARP scan complete: {} anomalies found", anomalies.len()))
}

let app = Router::new()
    .route("/health", get(arp_spoofing_detection));