icookforms 0.1.0

//! # Zero-Day Detector
//!
//! Detects unknown/zero-day cookie attacks using heuristics and ML.

use crate::types::{Cookie, Result};
use serde::{Deserialize, Serialize};

/// Zero-day attack detector
#[derive(Debug)]
pub struct ZeroDayDetector {
    #[allow(dead_code)]
    signatures: Vec<ZeroDaySignature>,
}

impl ZeroDayDetector {
    /// Create a new zero-day detector
    #[must_use]
    pub fn new() -> Self {
        Self {
            signatures: Vec::new(),
        }
    }

    /// Detect potential zero-day attacks
    pub fn detect(&self, cookies: &[Cookie]) -> Result<Vec<Cookie>> {
        let mut suspicious = Vec::new();

        for cookie in cookies {
            if Self::is_zero_day_candidate(cookie) {
                suspicious.push(cookie.clone());
            }
        }

        Ok(suspicious)
    }

    /// Check if cookie exhibits zero-day attack patterns
    fn is_zero_day_candidate(cookie: &Cookie) -> bool {
        // Heuristics for zero-day detection
        Self::has_unusual_structure(cookie)
            || Self::has_obfuscation(cookie)
            || Self::has_shellcode_patterns(cookie)
    }

    /// Check for unusual cookie structure
    fn has_unusual_structure(cookie: &Cookie) -> bool {
        // Very long values
        cookie.value.len() > 4096 ||
        // Multiple encoding layers
        cookie.value.matches("base64").count() > 2 ||
        // Unusual characters
        cookie.value.bytes().any(|b| b < 32 && b != b'\n' && b != b'\r' && b != b'\t')
    }

    /// Check for obfuscation patterns
    #[allow(clippy::cast_precision_loss)] // Small cookie value length, f64 precision acceptable
    fn has_obfuscation(cookie: &Cookie) -> bool {
        // High ratio of special characters
        let special_chars = cookie
            .value
            .chars()
            .filter(|c| !c.is_alphanumeric())
            .count();
        let ratio = special_chars as f64 / cookie.value.len() as f64;

        ratio > 0.5
    }

    /// Check for shellcode-like patterns
    fn has_shellcode_patterns(cookie: &Cookie) -> bool {
        // Hex patterns common in shellcode
        cookie.value.contains("\\x") ||
        cookie.value.contains("%u") ||
        // NOP sleds
        cookie.value.contains("\\x90\\x90")
    }
}

impl Default for ZeroDayDetector {
    fn default() -> Self {
        Self::new()
    }
}

/// Zero-day attack signature
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ZeroDaySignature {
    /// Signature name
    pub name: String,

    /// Detection heuristic
    pub heuristic: String,

    /// Confidence level (0.0-1.0)
    pub confidence: f64,
}

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

    #[test]
    fn test_zero_day_detector_creation() {
        let detector = ZeroDayDetector::new();
        assert!(detector.signatures.is_empty());
    }
}