added minhash algo when resp too short for ssdeep

src/filters/mod.rs

@@ -11,7 +11,7 @@ pub(crate) use self::empty::EmptyFilter;
 pub use self::init::initialize;
 pub use self::lines::LinesFilter;
 pub use self::regex::RegexFilter;
-pub use self::similarity::SimilarityFilter;
+pub use self::similarity::{SimilarityFilter, HashValueType};
 pub use self::size::SizeFilter;
 pub use self::status_code::StatusCodeFilter;
 pub(crate) use self::utils::{create_similarity_filter, filter_lookup};

src/filters/similarity.rs

@@ -1,12 +1,33 @@
+use std::hash::BuildHasherDefault;
+
 use super::*;
+use crate::MIN_SSDEEP_SIZE;
 use fuzzyhash::FuzzyHash;
+use gaoya::minhash::{MinHash, MinHasher, MinHasher16};
+use gaoya::text::whitespace_split;
+
+/// enum wrapper for two distinct hashing signature types
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub(crate) enum HashValueType {
+    /// String value for FuzzyHash
+    String(String),
+
+    /// Vec<u16> value for minhash
+    Vec(Vec<u16>),
+}
+
+impl Default for HashValueType {
+    fn default() -> Self {
+        Self::String(String::new())
+    }
+}
 
 /// Simple implementor of FeroxFilter; used to filter out responses based on the similarity of a
 /// Response body with a known response; specified using --filter-similar-to
 #[derive(Default, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct SimilarityFilter {
     /// Hash of Response's body to be used during similarity comparison
-    pub hash: String,
+    pub hash: HashValueType,
 
     /// Percentage of similarity at which a page is determined to be a near-duplicate of another
     pub threshold: u32,
@@ -20,11 +41,23 @@ impl FeroxFilter for SimilarityFilter {
     /// Check `FeroxResponse::text` against what was requested from the site passed in via
     /// --filter-similar-to
     fn should_filter_response(&self, response: &FeroxResponse) -> bool {
+        match self.hash {
+            HashValueType::String(ref hash) => {
+                // original response size was over the minimum required to effectively use ssdeep
                 let other = FuzzyHash::new(response.text());
 
-        if let Ok(result) = FuzzyHash::compare(&self.hash, other.to_string()) {
+                if let Ok(result) = FuzzyHash::compare(hash, other.to_string()) {
                     return result >= self.threshold;
                 }
+            }
+            HashValueType::Vec(ref hash) => {
+                // original response was too small for ssdeep, so minhash was used as an alternative
+                let hasher = MinHasher16::new(256);
+                let other = hasher.create_signature(whitespace_split(response.text()));
+                let result = hasher.compute_similarity(hash.iter(), other.iter());
+                return (result * 100.0) as u32 >= self.threshold;
+            }
+        }
 
         // couldn't hash the response, don't filter
         log::warn!(

src/filters/tests.rs

@@ -1,6 +1,7 @@
 use super::*;
 use ::fuzzyhash::FuzzyHash;
 use ::regex::Regex;
+use super::similarity::HashValueType;
 
 #[test]
 /// simply test the default values for wildcardfilter, expect 0, 0
@@ -186,7 +187,7 @@ fn similarity_filter_is_accurate() {
     resp.set_text("sitting");
 
     let mut filter = SimilarityFilter {
-        hash: FuzzyHash::new("kitten").to_string(),
+        hash: HashValueType::String(FuzzyHash::new("kitten").to_string()),
         threshold: 95,
         original_url: "".to_string(),
     };
@@ -195,14 +196,14 @@ fn similarity_filter_is_accurate() {
     assert!(!filter.should_filter_response(&resp));
 
     resp.set_text("");
-    filter.hash = String::new();
+    filter.hash = HashValueType::String(String::new());
     filter.threshold = 100;
 
     // two empty strings are the same, however ssdeep doesn't accept empty strings, expect false
     assert!(!filter.should_filter_response(&resp));
 
     resp.set_text("some data to hash for the purposes of running a test");
-    filter.hash = FuzzyHash::new("some data to hash for the purposes of running a te").to_string();
+    filter.hash = HashValueType::String(FuzzyHash::new("some data to hash for the purposes of running a te").to_string());
     filter.threshold = 17;
 
     assert!(filter.should_filter_response(&resp));
@@ -212,20 +213,19 @@ fn similarity_filter_is_accurate() {
 /// just a simple test to increase code coverage by hitting as_any and the inner value
 fn similarity_filter_as_any() {
     let filter = SimilarityFilter {
-        hash: String::from("stuff"),
+        hash: HashValueType::String(String::from("stuff")),
         threshold: 95,
         original_url: "".to_string(),
     };
 
     let filter2 = SimilarityFilter {
-        hash: String::from("stuff"),
+        hash: HashValueType::String(String::from("stuff")),
         threshold: 95,
         original_url: "".to_string(),
     };
 
     assert!(filter.box_eq(filter2.as_any()));
 
-    assert_eq!(filter.hash, "stuff");
     assert_eq!(
         *filter.as_any().downcast_ref::<SimilarityFilter>().unwrap(),
         filter

src/filters/utils.rs

@@ -1,11 +1,14 @@
+use super::similarity::HashValueType;
 use super::FeroxFilter;
 use super::SimilarityFilter;
 use crate::event_handlers::Handles;
 use crate::response::FeroxResponse;
 use crate::utils::logged_request;
-use crate::{DEFAULT_METHOD, SIMILARITY_THRESHOLD};
+use crate::{DEFAULT_METHOD, MIN_SSDEEP_SIZE, SIMILARITY_THRESHOLD};
 use anyhow::Result;
 use fuzzyhash::FuzzyHash;
+use gaoya::minhash::{MinHasher, MinHasher16};
+use gaoya::text::whitespace_split;
 use regex::Regex;
 use reqwest::Url;
 use std::sync::Arc;
@@ -41,7 +44,14 @@ pub(crate) async fn create_similarity_filter(
     }
 
     // hash the response body and store the resulting hash in the filter object
-    let hash = FuzzyHash::new(fr.text()).to_string();
+    let hash = if fr.content_length() <= MIN_SSDEEP_SIZE {
+        // response too small for ssdeep
+        let hasher = MinHasher16::new(256);
+        HashValueType::Vec(hasher.create_signature(whitespace_split(fr.text())))
+    } else {
+        // size over ssdeep's minimum value
+        HashValueType::String(FuzzyHash::new(fr.text()).to_string())
+    };
 
     Ok(SimilarityFilter {
         hash,
@@ -95,7 +105,7 @@ pub(crate) fn filter_lookup(filter_type: &str, filter_value: &str) -> Option<Box
         }
         "similarity" => {
             return Some(Box::new(SimilarityFilter {
-                hash: String::new(),
+                hash: HashValueType::String(String::new()),
                 threshold: SIMILARITY_THRESHOLD,
                 original_url: filter_value.to_string(),
             }));
@@ -157,7 +167,7 @@ mod tests {
         assert_eq!(
             filter.as_any().downcast_ref::<SimilarityFilter>().unwrap(),
             &SimilarityFilter {
-                hash: String::new(),
+                hash: HashValueType::String(String::new()),
                 threshold: SIMILARITY_THRESHOLD,
                 original_url: "http://localhost".to_string()
             }
@@ -195,7 +205,7 @@ mod tests {
         assert_eq!(
             filter,
             SimilarityFilter {
-                hash: "3:YKEpn:Yfp".to_string(),
+                hash: HashValueType::String("3:YKEpn:Yfp".to_string()),
                 threshold: SIMILARITY_THRESHOLD,
                 original_url: srv.url("/")
             }

src/heuristics.rs

@@ -5,7 +5,6 @@ use console::style;
 use scraper::{Html, Selector};
 use uuid::Uuid;
 
-use crate::filters::SimilarityFilter;
 use crate::message::FeroxMessage;
 use crate::{
     config::OutputLevel,

src/lib.rs

@@ -55,6 +55,11 @@ pub const DEFAULT_OPEN_FILE_LIMIT: u64 = 8192;
 /// Default value used to determine near-duplicate web pages (equivalent to 95%)
 pub const SIMILARITY_THRESHOLD: u32 = 95;
 
+/// Minimum size of response body for ssdeep to produce meaningful results
+/// 
+/// ref: https://github.com/glaslos/ssdeep/issues/17
+pub(crate) const MIN_SSDEEP_SIZE: u64 = 4096;
+
 /// Default set of extensions to Ignore when auto-collecting extensions during scans
 pub(crate) const DEFAULT_IGNORED_EXTENSIONS: [&str; 38] = [
     "tif", "tiff", "ico", "cur", "bmp", "webp", "svg", "png", "jpg", "jpeg", "jfif", "gif", "avif",

src/scan_manager/tests.rs

@@ -1,7 +1,7 @@
 use super::*;
 use crate::filters::{
     FeroxFilters, LinesFilter, RegexFilter, SimilarityFilter, SizeFilter, StatusCodeFilter,
-    WordsFilter,
+    WordsFilter,HashValueType
 };
 use crate::{
     config::{Configuration, OutputLevel},
@@ -399,7 +399,7 @@ fn feroxstates_feroxserialize_implementation() {
         .unwrap();
     filters
         .push(Box::new(SimilarityFilter {
-            hash: "3:YKEpn:Yfp".to_string(),
+            hash: HashValueType::String("3:YKEpn:Yfp".to_string()),
             threshold: SIMILARITY_THRESHOLD,
             original_url: "http://localhost:12345/".to_string(),
         }))