diff --git a/src/banner/container.rs b/src/banner/container.rs
index 59a6d71..2f94970 100644
--- a/src/banner/container.rs
+++ b/src/banner/container.rs
@@ -188,13 +188,13 @@ impl Banner {
             targets.push(BannerEntry::new("🎯", "Target Url", target));
         }
 
-        for denied_url in &config.url_denylist {
-            url_denylist.push(BannerEntry::new(
-                "🚫",
-                "Don't Scan Url",
-                denied_url.as_str(),
-            ));
-        }
+        // for denied_url in &config.url_denylist {
+        //     url_denylist.push(BannerEntry::new(
+        //         "🚫",
+        //         "Don't Scan Url",
+        //         denied_url.as_str(),
+        //     ));
+        // }
 
         for denied_regex in &config.regex_denylist {
             url_denylist.push(BannerEntry::new(
diff --git a/src/config/container.rs b/src/config/container.rs
index 8cd3bc4..aeeb71a 100644
--- a/src/config/container.rs
+++ b/src/config/container.rs
@@ -13,6 +13,7 @@ use clap::{parser::ValueSource, ArgMatches};
 use regex::Regex;
 use reqwest::{Client, Method, StatusCode, Url};
 use serde::{Deserialize, Serialize};
+use std::sync::{Arc, RwLock};
 use std::{
     collections::HashMap,
     env::{current_dir, current_exe},
@@ -284,7 +285,7 @@ pub struct Configuration {
 
     /// URLs that should never be scanned/recursed into
     #[serde(default)]
-    pub url_denylist: Vec<Url>,
+    pub url_denylist: Arc<RwLock<Vec<Url>>>,
 
     /// URLs that should never be scanned/recursed into based on a regular expression
     #[serde(with = "serde_regex", default)]
@@ -372,7 +373,7 @@ impl Default for Configuration {
             data: Vec::new(),
             filter_size: Vec::new(),
             filter_regex: Vec::new(),
-            url_denylist: Vec::new(),
+            url_denylist: Arc::new(RwLock::new(Vec::new())),
             regex_denylist: Vec::new(),
             filter_line_count: Vec::new(),
             filter_word_count: Vec::new(),
@@ -668,7 +669,9 @@ impl Configuration {
                 match Url::parse(denier.trim_end_matches('/')) {
                     Ok(absolute) => {
                         // denier is an absolute url and can be parsed as such
-                        config.url_denylist.push(absolute);
+                        if let Ok(mut guard) = config.url_denylist.write() {
+                            guard.push(absolute);
+                        }
                     }
                     Err(err) => {
                         // there are some expected errors that happen when we try to parse a url
@@ -991,7 +994,12 @@ impl Configuration {
         update_if_not_default!(&mut conf.extensions, new.extensions, Vec::<String>::new());
         update_if_not_default!(&mut conf.methods, new.methods, methods());
         update_if_not_default!(&mut conf.data, new.data, Vec::<u8>::new());
-        update_if_not_default!(&mut conf.url_denylist, new.url_denylist, Vec::<Url>::new());
+        // update_if_not_default!(
+        //     &mut conf.url_denylist,
+        //     new.url_denylist,
+        //     Arc::new(RwLock::new(Vec::<Url>::new()))
+        // );
+        // todo: fix this above
         if !new.regex_denylist.is_empty() {
             // cant use the update_if_not_default macro due to the following error
             //
diff --git a/src/config/tests.rs b/src/config/tests.rs
index 778ece4..1e7b344 100644
--- a/src/config/tests.rs
+++ b/src/config/tests.rs
@@ -3,6 +3,7 @@ use super::*;
 use crate::{traits::FeroxSerialize, DEFAULT_CONFIG_NAME};
 use regex::Regex;
 use reqwest::Url;
+use std::sync::{Arc, RwLock};
 use std::{collections::HashMap, fs::write};
 use tempfile::TempDir;
 
@@ -109,7 +110,10 @@ fn default_configuration() {
     assert_eq!(config.extensions, Vec::<String>::new());
     assert_eq!(config.methods, vec!["GET"]);
     assert_eq!(config.data, Vec::<u8>::new());
-    assert_eq!(config.url_denylist, Vec::<Url>::new());
+    assert_eq!(
+        config.url_denylist,
+        Arc::new(RwLock::new(Vec::<Url>::new()))
+    );
     assert_eq!(config.dont_collect, ignored_extensions());
     assert_eq!(config.filter_regex, Vec::<String>::new());
     assert_eq!(config.filter_similar, Vec::<String>::new());
diff --git a/src/event_handlers/scans.rs b/src/event_handlers/scans.rs
index 8329c20..a71a5b1 100644
--- a/src/event_handlers/scans.rs
+++ b/src/event_handlers/scans.rs
@@ -312,8 +312,14 @@ impl ScanHandler {
     /// wrapper around scanning a url to stay DRY
     async fn ordered_scan_url(&mut self, targets: Vec<String>, order: ScanOrder) -> Result<()> {
         log::trace!("enter: ordered_scan_url({:?}, {:?})", targets, order);
-        let should_test_deny = !self.handles.config.url_denylist.is_empty()
-            || !self.handles.config.regex_denylist.is_empty();
+        
+        let url_denylist_is_not_empty = if let Ok(guard) = self.handles.config.url_denylist.read() {
+            !guard.is_empty()
+        } else {
+            false
+        };
+        let should_test_deny =
+            url_denylist_is_not_empty || !self.handles.config.regex_denylist.is_empty();
 
         for target in targets {
             if self.data.contains(&target) && matches!(order, ScanOrder::Latest) {
diff --git a/src/extractor/container.rs b/src/extractor/container.rs
index e7f5e1f..348b38f 100644
--- a/src/extractor/container.rs
+++ b/src/extractor/container.rs
@@ -430,8 +430,13 @@ impl<'a> Extractor<'a> {
             bail!("previously seen url");
         }
 
-        if (!self.handles.config.url_denylist.is_empty()
-            || !self.handles.config.regex_denylist.is_empty())
+        let url_denylist_is_not_empty = if let Ok(guard) = self.handles.config.url_denylist.read() {
+            !guard.is_empty()
+        } else {
+            false
+        };
+
+        if (url_denylist_is_not_empty || !self.handles.config.regex_denylist.is_empty())
             && should_deny_url(&new_url, self.handles.clone())?
         {
             // can't allow a denied url to be requested
diff --git a/src/heuristics.rs b/src/heuristics.rs
index 66d6275..b1cb479 100644
--- a/src/heuristics.rs
+++ b/src/heuristics.rs
@@ -360,6 +360,21 @@ impl HeuristicTests {
                 .filters
                 .send(Command::AddFilter(Box::new(sim_filter)))?;
 
+            if let Ok(mut guard) = self.handles.config.url_denylist.write() {
+                use reqwest::Url;
+                // todo need to get the parent
+                log::warn!("FOUND 404 LIKE RESPONSE: {:?}", responses[0].url());
+                let derp = responses[0].url().as_str();
+                let mut new_url = Url::parse(derp).unwrap();
+                new_url.path_segments_mut().unwrap().pop();
+                // responses[0].url().set_path(path_segments.as_str());
+                log::warn!(
+                    "ADDING PARENT OF 404 LIKE RESPONSE: {:?}",
+                    new_url
+                );
+                guard.push(new_url);
+            }
+
             // reset the responses for the next method, if it exists
             responses.clear();
 
diff --git a/src/main.rs b/src/main.rs
index a81dcd1..734b1c5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -182,13 +182,15 @@ async fn get_targets(handles: Arc<Handles>) -> Result<Vec<String>> {
                 );
             }
         }
-        for denier in &handles.config.url_denylist {
-            if denier.as_str().trim_end_matches('/') == target.trim_end_matches('/') {
-                bail!(
-                    "The url '{}' matches {}; the scan will never start",
-                    denier,
-                    target
-                );
+        if let Ok(guard) = handles.config.url_denylist.read() {
+            for denier in guard.iter() {
+                if denier.as_str().trim_end_matches('/') == target.trim_end_matches('/') {
+                    bail!(
+                        "The url '{}' matches {}; the scan will never start",
+                        denier,
+                        target
+                    );
+                }
             }
         }
 
diff --git a/src/scanner/requester.rs b/src/scanner/requester.rs
index bc69a8c..6e5c909 100644
--- a/src/scanner/requester.rs
+++ b/src/scanner/requester.rs
@@ -353,8 +353,14 @@ impl Requester {
         let urls = FeroxUrl::from_string(&self.target_url, self.handles.clone())
             .formatted_urls(word, collected)?;
 
-        let should_test_deny = !self.handles.config.url_denylist.is_empty()
-            || !self.handles.config.regex_denylist.is_empty();
+        let url_denylist_is_not_empty = if let Ok(guard) = self.handles.config.url_denylist.read() {
+            !guard.is_empty()
+        } else {
+            false
+        };
+
+        let should_test_deny =
+            url_denylist_is_not_empty || !self.handles.config.regex_denylist.is_empty();
 
         for url in urls {
             for method in self.handles.config.methods.iter() {
diff --git a/src/utils.rs b/src/utils.rs
index 754b2e5..6e685b1 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -484,12 +484,14 @@ pub fn should_deny_url(url: &Url, handles: Arc<Handles>) -> Result<bool> {
     // the given url and any url to which it's compared
     let normed_url = Url::parse(url.to_string().trim_end_matches('/'))?;
 
-    for denier in &handles.config.url_denylist {
-        // note to self: it may seem as though we can use regex only for --dont-scan, however, in
-        // doing so, we lose the ability to block a parent directory while scanning a child
-        if let Ok(should_deny) = should_deny_absolute(&normed_url, denier, handles.clone()) {
-            if should_deny {
-                return Ok(true);
+    if let Ok(guard) = handles.config.url_denylist.read() {
+        for denier in guard.iter() {
+            // note to self: it may seem as though we can use regex only for --dont-scan, however, in
+            // doing so, we lose the ability to block a parent directory while scanning a child
+            if let Ok(should_deny) = should_deny_absolute(&normed_url, denier, handles.clone()) {
+                if should_deny {
+                    return Ok(true);
+                }
             }
         }
     }