security-rust 1.0.7

A pure Rust attack detection library with 27 detectors across 4 categories — injection, protocol, data, and file attacks. Zero framework dependencies.
Documentation 
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// Copyright (c) 2026 erik <erik@erik.xyz> — https://erik.xyz

use regex::Regex;
use std::sync::LazyLock;

use crate::{regex_detect, AttackCategory, DetectionResult, Detector, Severity};

static PATTERNS: LazyLock<Vec<Regex>> = LazyLock::new(|| {
    vec![
        Regex::new(r"(?i)\r\n.*Host:").unwrap(),
        Regex::new(r"(?i)\r\n.*X-Forwarded").unwrap(),
        Regex::new(r"(?i)\r\n.*X-Original-URL").unwrap(),
        Regex::new(r"(?i)\r\n.*X-Rewrite-URL").unwrap(),
    ]
});

pub struct HostHeaderDetector;

impl Detector for HostHeaderDetector {
    fn name(&self) -> &'static str {
        "host_header"
    }

    fn detect(&self, input: &str) -> Option<DetectionResult> {
        regex_detect(&PATTERNS, self.name(), AttackCategory::Protocol, Severity::High, "Host header attack detected", input)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn assert_detected(input: &str) {
        crate::test_helpers::assert_detected(
            &HostHeaderDetector,
            input,
            AttackCategory::Protocol,
            Severity::High,
        );
    }

    fn assert_clean(input: &str) {
        crate::test_helpers::assert_clean(&HostHeaderDetector, input);
    }

    #[test]
    fn name_is_host_header() {
        assert_eq!(HostHeaderDetector.name(), "host_header");
    }

    #[test]
    fn detects_x_forwarded_host() {
        assert_detected("Host: example.com\r\nX-Forwarded-Host: evil.com");
    }

    #[test]
    fn detects_injected_host_line() {
        assert_detected("GET / HTTP/1.1\r\nHost: evil.com");
    }

    #[test]
    fn detects_x_original_url() {
        assert_detected("Host: a.com\r\nX-Original-URL: /admin");
    }

    #[test]
    fn detects_x_rewrite_url() {
        assert_detected("Host: a.com\r\nX-Rewrite-URL: /admin");
    }

    #[test]
    fn detects_x_forwarded_for() {
        assert_detected("Host: a.com\r\nX-Forwarded-For: 1.2.3.4");
    }

    #[test]
    fn detects_mixed_case() {
        assert_detected("host: example.com\r\nx-forwarded-host: evil.com");
    }

    #[test]
    fn rejects_single_header_lines() {
        assert_clean("Host: example.com");
        assert_clean("X-Forwarded-Host: evil.com");
        assert_clean("Host: example.com\r\nAccept: */*");
    }

    #[test]
    fn rejects_lf_only_newlines() {
        assert_clean("Host: example.com\nX-Forwarded-Host: evil.com");
    }

    #[test]
    fn rejects_empty_and_whitespace() {
        assert_clean("");
        assert_clean("   ");
    }

    #[test]
    fn rejects_unicode_text() {
        assert_clean("主机头示例，无攻击");
    }
}