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\s*(?:Set-Cookie|Location|Content-Length|Content-Type|Transfer-Encoding):",
        )
        .unwrap(),
        Regex::new(r"(?i)%0[dD].*%0[aA]").unwrap(),
    ]
});

pub struct HeaderInjectionDetector;

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

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

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

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

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

    #[test]
    fn name_is_header_injection() {
        assert_eq!(HeaderInjectionDetector.name(), "header_injection");
    }

    #[test]
    fn detects_encoded_crlf_set_cookie() {
        assert_detected("test%0d%0aSet-Cookie: evil=true");
    }

    #[test]
    fn detects_encoded_crlf_location() {
        assert_detected("redirect?url=%0D%0ALocation: /admin");
    }

    #[test]
    fn detects_encoded_crlf_content_length() {
        assert_detected("body%0d%0aContent-Length: 0");
    }

    #[test]
    fn detects_raw_crlf_headers() {
        assert_detected("foo\r\nContent-Type: text/html");
        assert_detected("bar\r\nTransfer-Encoding: chunked");
    }

    #[test]
    fn detects_scattered_encoded_crlf() {
        assert_detected("a%0dcontent%0a");
    }

    #[test]
    fn rejects_clean_headers() {
        assert_clean("Set-Cookie: evil=true");
        assert_clean("Location: /index.php");
        assert_clean("Content-Type: text/html");
    }

    #[test]
    fn rejects_lone_encoded_chars() {
        assert_clean("%0d");
        assert_clean("%0a");
        assert_clean("test%0dend");
        assert_clean("%0d%0d");
    }

    #[test]
    fn rejects_lf_only_newlines() {
        assert_clean("foo\nContent-Type: text/html");
        assert_clean("foo\nLocation: /x");
    }

    #[test]
    fn rejects_near_misses() {
        assert_clean("foo\r\nContent-Type text/html");
    }

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

    #[test]
    fn rejects_unicode_text() {
        assert_clean("这是一段正常文本，无注入");
    }
}