Merge pull request #222 from epi052/213-add-parallel-option

add --parallel option

.github/pull_request_template.md

@@ -7,7 +7,7 @@ Long form explanations of most of the items below can be found in the [CONTRIBUT
 - [ ] Your PR description references the associated issue (i.e. fixes #123456)
 - [ ] Code is in its own branch
 - [ ] Branch name is related to the PR contents
-- [ ] PR targets master
+- [ ] PR targets main
 
 ## Static analysis checks
 - [ ] All rust files are formatted using `cargo fmt`

Cargo.lock

@@ -633,7 +633,7 @@ dependencies = [
 
 [[package]]
 name = "feroxbuster"
-version = "2.1.0"
+version = "2.2.0"
 dependencies = [
  "anyhow",
  "assert_cmd",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "feroxbuster"
-version = "2.1.0"
+version = "2.2.0"
 authors = ["Ben 'epi' Risher <epibar052@gmail.com>"]
 license = "MIT"
 edition = "2018"
@@ -22,7 +22,7 @@ lazy_static = "1.4"
 
 [dependencies]
 futures = { version = "0.3"}
-tokio = { version = "1.0", features = ["full"] }
+tokio = { version = "1.2.0", features = ["full"] }
 tokio-util = {version = "0.6.3", features = ["codec"]}
 log = "0.4"
 env_logger = "0.8.3"
@@ -31,7 +31,7 @@ clap = "2.33"
 lazy_static = "1.4"
 toml = "0.5"
 serde = { version = "1.0", features = ["derive", "rc"] }
-serde_json = "1.0"
+serde_json = "1.0.62"
 uuid = { version = "0.8", features = ["v4"] }
 indicatif = "0.15"
 console = "0.14"

README.md

@@ -105,6 +105,7 @@ Enumeration.
     - [Limit Number of Requests per Second (Rate Limiting) (new in `v2.0.0`)](#limit-number-of-requests-per-second-rate-limiting-new-in-v200)
     - [Silence all Output or Be Kinda Quiet (new in `v2.0.0`)](#silence-all-output-or-be-kinda-quiet-new-in-v200)
     - [Auto-tune or Auto-bail from Scans (new in `v2.1.0`)](#auto-tune-or-auto-bail-from-scans-new-in-v210)
+    - [Run Scans in Parallel (new in `v2.2.0`)](#run-scans-in-parallel-new-in-v220)
 - [Comparison w/ Similar Tools](#-comparison-w-similar-tools)
 - [Common Problems/Issues (FAQ)](#-common-problemsissues-faq)
     - [No file descriptors available](#no-file-descriptors-available)
@@ -370,6 +371,7 @@ A pre-made configuration file with examples of all available settings can be fou
 # status_codes = [200, 500]
 # filter_status = [301]
 # threads = 1
+# parallel = 2
 # timeout = 5
 # auto_tune = true
 # auto_bail = true
@@ -463,6 +465,9 @@ OPTIONS:
     -W, --filter-words <WORDS>...                 Filter out messages of a particular word count (ex: -W 312 -W 91,82)
     -H, --headers <HEADER>...                     Specify HTTP headers (ex: -H Header:val 'stuff: things')
     -o, --output <FILE>                           Output file to write results to (use w/ --json for JSON entries)
+        --parallel <PARALLEL_SCANS>
+            Run parallel feroxbuster instances (one child process per url passed via stdin)
+
     -p, --proxy <PROXY>
             Proxy to use for requests (ex: http(s)://host:port, socks5(h)://host:port)
 
@@ -898,6 +903,29 @@ The AutoBail policy aborts individual directory scans when one of the criteria a
 
 ![auto-bail](img/auto-bail-demo.gif)
 
+### Run Scans in Parallel (new in `v2.2.0`)
+
+Version 2.2.0 introduces the `--parallel` option.  If you're one of those people who use `feroxbuster` to scan 100s of hosts at a time, this is the option for you! `--parallel` spawns a child process per target passed in over stdin (recursive directories are still async within each child).
+
+The number of parallel scans is limited to whatever you pass to `--parallel`. When one child finishes its scan, the next child will be spawned.  
+
+Unfortunately, using `--parallel` limits terminal output such that only discovered URLs are shown. No amount of `-v`'s will help you here. I imagine this isn't too big of a deal, as folks that need `--parallel` probably aren't sitting there watching the output... 🙃
+
+Example Command:
+```
+cat large-target-list | ./feroxbuster --stdin --parallel 10 --extract-links --auto-bail
+```
+
+Resuling Process List (illustrative):
+```
+\_ target/debug/feroxbuster --stdin --parallel 10
+    \_ target/debug/feroxbuster --silent --extract-links --auto-bail -u https://target-one
+    \_ target/debug/feroxbuster --silent --extract-links --auto-bail -u https://target-two
+    \_ target/debug/feroxbuster --silent --extract-links --auto-bail -u https://target-three
+    \_ ...
+    \_ target/debug/feroxbuster --silent --extract-links --auto-bail -u https://target-ten
+```
+
 ## 🧐 Comparison w/ Similar Tools
 
 There are quite a few similar tools for forced browsing/content discovery. Burp Suite Pro, Dirb, Dirbuster, etc...
@@ -947,6 +975,7 @@ few of the use-cases in which feroxbuster may be a better fit:
 | hide progress bars or be silent (or some variation) (`v2.0.0`)               | ✔ | ✔ | ✔ |
 | automatically tune scans based on errors/403s/429s  (`v2.1.0`)               | ✔ |   |   |
 | automatically stop scans based on errors/403s/429s  (`v2.1.0`)               | ✔ |   | ✔ |
+| run scans in parallel (1 process per target) (`v2.2.0`)                      | ✔ |   |   |
 | **huge** number of other options                                             |   |   | ✔ |
 
 Of note, there's another written-in-rust content discovery tool, [rustbuster](https://github.com/phra/rustbuster). I

ferox-config.toml.example

@@ -16,6 +16,7 @@
 # replay_proxy = "http://127.0.0.1:8081"
 # replay_codes = [200, 302]
 # verbosity = 1
+# parallel = 8
 # scan_limit = 6
 # rate_limit = 250
 # quiet = true

shell_completions/_feroxbuster

@@ -58,6 +58,7 @@ _feroxbuster() {
 '*--filter-similar-to=[Filter out pages that are similar to the given page (ex. --filter-similar-to http://site.xyz/soft404)]' \
 '-L+[Limit total number of concurrent scans (default: 0, i.e. no limit)]' \
 '--scan-limit=[Limit total number of concurrent scans (default: 0, i.e. no limit)]' \
+'--parallel=[Run parallel feroxbuster instances (one child process per url passed via stdin)]' \
 '(--auto-tune)--rate-limit=[Limit number of requests per second (per directory) (default: 0, i.e. no limit)]' \
 '--time-limit=[Limit total run time of all scans (ex: --time-limit 10m)]' \
 '(--silent)*-v[Increase verbosity level (use -vv or more for greater effect. \[CAUTION\] 4 -v'\''s is probably too much)]' \

shell_completions/_feroxbuster.ps1

@@ -63,6 +63,7 @@ Register-ArgumentCompleter -Native -CommandName 'feroxbuster' -ScriptBlock {
             [CompletionResult]::new('--filter-similar-to', 'filter-similar-to', [CompletionResultType]::ParameterName, 'Filter out pages that are similar to the given page (ex. --filter-similar-to http://site.xyz/soft404)')
             [CompletionResult]::new('-L', 'L', [CompletionResultType]::ParameterName, 'Limit total number of concurrent scans (default: 0, i.e. no limit)')
             [CompletionResult]::new('--scan-limit', 'scan-limit', [CompletionResultType]::ParameterName, 'Limit total number of concurrent scans (default: 0, i.e. no limit)')
+            [CompletionResult]::new('--parallel', 'parallel', [CompletionResultType]::ParameterName, 'Run parallel feroxbuster instances (one child process per url passed via stdin)')
             [CompletionResult]::new('--rate-limit', 'rate-limit', [CompletionResultType]::ParameterName, 'Limit number of requests per second (per directory) (default: 0, i.e. no limit)')
             [CompletionResult]::new('--time-limit', 'time-limit', [CompletionResultType]::ParameterName, 'Limit total run time of all scans (ex: --time-limit 10m)')
             [CompletionResult]::new('-v', 'v', [CompletionResultType]::ParameterName, 'Increase verbosity level (use -vv or more for greater effect. [CAUTION] 4 -v''s is probably too much)')

shell_completions/feroxbuster.bash

@@ -20,7 +20,7 @@ _feroxbuster() {
 
     case "${cmd}" in
         feroxbuster)
-            opts=" -v -q -D -r -k -n -f -e -h -V -w -u -t -d -T -p -P -R -s -o -a -x -H -Q -S -X -W -N -C -L  --verbosity --silent --quiet --auto-tune --auto-bail --json --dont-filter --redirects --insecure --no-recursion --add-slash --stdin --extract-links --help --version --wordlist --url --threads --depth --timeout --proxy --replay-proxy --replay-codes --status-codes --output --resume-from --debug-log --user-agent --extensions --headers --query --filter-size --filter-regex --filter-words --filter-lines --filter-status --filter-similar-to --scan-limit --rate-limit --time-limit  "
+            opts=" -v -q -D -r -k -n -f -e -h -V -w -u -t -d -T -p -P -R -s -o -a -x -H -Q -S -X -W -N -C -L  --verbosity --silent --quiet --auto-tune --auto-bail --json --dont-filter --redirects --insecure --no-recursion --add-slash --stdin --extract-links --help --version --wordlist --url --threads --depth --timeout --proxy --replay-proxy --replay-codes --status-codes --output --resume-from --debug-log --user-agent --extensions --headers --query --filter-size --filter-regex --filter-words --filter-lines --filter-status --filter-similar-to --scan-limit --parallel --rate-limit --time-limit  "
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 1 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -199,6 +199,10 @@ _feroxbuster() {
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0
                     ;;
+                --parallel)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
                 --rate-limit)
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0

shell_completions/feroxbuster.fish

@@ -21,6 +21,7 @@ complete -c feroxbuster -n "__fish_use_subcommand" -s N -l filter-lines -d 'Filt
 complete -c feroxbuster -n "__fish_use_subcommand" -s C -l filter-status -d 'Filter out status codes (deny list) (ex: -C 200 -C 401)'
 complete -c feroxbuster -n "__fish_use_subcommand" -l filter-similar-to -d 'Filter out pages that are similar to the given page (ex. --filter-similar-to http://site.xyz/soft404)'
 complete -c feroxbuster -n "__fish_use_subcommand" -s L -l scan-limit -d 'Limit total number of concurrent scans (default: 0, i.e. no limit)'
+complete -c feroxbuster -n "__fish_use_subcommand" -l parallel -d 'Run parallel feroxbuster instances (one child process per url passed via stdin)'
 complete -c feroxbuster -n "__fish_use_subcommand" -l rate-limit -d 'Limit number of requests per second (per directory) (default: 0, i.e. no limit)'
 complete -c feroxbuster -n "__fish_use_subcommand" -l time-limit -d 'Limit total run time of all scans (ex: --time-limit 10m)'
 complete -c feroxbuster -n "__fish_use_subcommand" -s v -l verbosity -d 'Increase verbosity level (use -vv or more for greater effect. [CAUTION] 4 -v\'s is probably too much)'

src/banner/container.rs

@@ -125,6 +125,9 @@ pub struct Banner {
     /// represents Configuration.rate_limit
     rate_limit: BannerEntry,
 
+    /// represents Configuration.parallel
+    parallel: BannerEntry,
+
     /// represents Configuration.auto_tune
     auto_tune: BannerEntry,
 
@@ -281,6 +284,7 @@ impl Banner {
             BannerEntry::new("🤪", "Filter Wildcards", &(!config.dont_filter).to_string());
         let add_slash = BannerEntry::new("🪓", "Add Slash", &config.add_slash.to_string());
         let time_limit = BannerEntry::new("🕖", "Time Limit", &config.time_limit);
+        let parallel = BannerEntry::new("🛤", "Parallel Scans", &config.parallel.to_string());
         let rate_limit =
             BannerEntry::new("🚧", "Requests per Second", &config.rate_limit.to_string());
 
@@ -304,6 +308,7 @@ impl Banner {
             filter_line_count,
             filter_regex,
             extract_links,
+            parallel,
             json,
             queries,
             output,
@@ -518,6 +523,10 @@ by Ben "epi" Risher {}                 ver: {}"#,
             writeln!(&mut writer, "{}", self.scan_limit)?;
         }
 
+        if config.parallel > 0 {
+            writeln!(&mut writer, "{}", self.parallel)?;
+        }
+
         if config.rate_limit > 0 {
             writeln!(&mut writer, "{}", self.rate_limit)?;
         }

src/config/container.rs

@@ -198,6 +198,10 @@ pub struct Configuration {
     #[serde(default)]
     pub scan_limit: usize,
 
+    /// Number of parallel scans permitted; a limit of 0 means no limit is imposed
+    #[serde(default)]
+    pub parallel: usize,
+
     /// Number of requests per second permitted (per directory); a limit of 0 means no limit is imposed
     #[serde(default)]
     pub rate_limit: usize,
@@ -280,6 +284,7 @@ impl Default for Configuration {
             json: false,
             verbosity: 0,
             scan_limit: 0,
+            parallel: 0,
             rate_limit: 0,
             add_slash: false,
             insecure: false,
@@ -350,7 +355,8 @@ impl Configuration {
     /// - **dont_filter**: `false` (auto filter wildcard responses)
     /// - **depth**: `4` (maximum recursion depth)
     /// - **scan_limit**: `0` (no limit on concurrent scans imposed)
-    /// - **rate_limit**: `0` (no limit on concurrent scans imposed)
+    /// - **parallel**: `0` (no limit on parallel scans imposed)
+    /// - **rate_limit**: `0` (no limit on requests per second imposed)
     /// - **time_limit**: `None` (no limit on length of scan imposed)
     /// - **replay_proxy**: `None` (no limit on concurrent scans imposed)
     /// - **replay_codes**: [`DEFAULT_RESPONSE_CODES`](constant.DEFAULT_RESPONSE_CODES.html)
@@ -486,6 +492,7 @@ impl Configuration {
         update_config_if_present!(&mut config.threads, args, "threads", usize);
         update_config_if_present!(&mut config.depth, args, "depth", usize);
         update_config_if_present!(&mut config.scan_limit, args, "scan_limit", usize);
+        update_config_if_present!(&mut config.parallel, args, "parallel", usize);
         update_config_if_present!(&mut config.rate_limit, args, "rate_limit", usize);
         update_config_if_present!(&mut config.wordlist, args, "wordlist", String);
         update_config_if_present!(&mut config.output, args, "output", String);
@@ -793,6 +800,7 @@ impl Configuration {
         );
         update_if_not_default!(&mut conf.dont_filter, new.dont_filter, false);
         update_if_not_default!(&mut conf.scan_limit, new.scan_limit, 0);
+        update_if_not_default!(&mut conf.parallel, new.parallel, 0);
         update_if_not_default!(&mut conf.rate_limit, new.rate_limit, 0);
         update_if_not_default!(&mut conf.replay_proxy, new.replay_proxy, "");
         update_if_not_default!(&mut conf.debug_log, new.debug_log, "");

src/config/tests.rs

@@ -20,6 +20,7 @@ fn setup_config_test() -> Configuration {
             auto_bail = true
             verbosity = 1
             scan_limit = 6
+            parallel = 14
             rate_limit = 250
             time_limit = "10m"
             output = "/some/otherpath"
@@ -146,6 +147,13 @@ fn config_reads_scan_limit() {
     assert_eq!(config.scan_limit, 6);
 }
 
+#[test]
+/// parse the test config and see that the value parsed is correct
+fn config_reads_parallel() {
+    let config = setup_config_test();
+    assert_eq!(config.parallel, 14);
+}
+
 #[test]
 /// parse the test config and see that the value parsed is correct
 fn config_reads_rate_limit() {

src/main.rs

@@ -1,13 +1,19 @@
 use std::{
     collections::HashSet,
+    env::args,
     fs::File,
     io::{stderr, BufRead, BufReader},
+    ops::Index,
+    process::Command,
     sync::{atomic::Ordering, Arc},
 };
 
 use anyhow::{bail, Context, Result};
 use futures::StreamExt;
-use tokio::{io, sync::oneshot};
+use tokio::{
+    io,
+    sync::{oneshot, Semaphore},
+};
 use tokio_util::codec::{FramedRead, LinesCodec};
 
 use feroxbuster::{
@@ -26,6 +32,13 @@ use feroxbuster::{
 };
 #[cfg(not(target_os = "windows"))]
 use feroxbuster::{utils::set_open_file_limit, DEFAULT_OPEN_FILE_LIMIT};
+use lazy_static::lazy_static;
+use regex::Regex;
+
+lazy_static! {
+    /// Limits the number of parallel scans active at any given time when using --parallel
+    static ref PARALLEL_LIMITER: Semaphore = Semaphore::new(0);
+}
 
 /// Create a HashSet of Strings from the given wordlist then stores it inside an Arc
 fn get_unique_words_from_wordlist(path: &str) -> Result<Arc<HashSet<String>>> {
@@ -226,6 +239,72 @@ async fn wrapped_main(config: Arc<Configuration>) -> Result<()> {
         }
     };
 
+    // --parallel branch
+    if config.parallel > 0 {
+        log::trace!("enter: parallel branch");
+
+        PARALLEL_LIMITER.add_permits(config.parallel);
+
+        let invocation = args();
+
+        let para_regex =
+            Regex::new("--stdin|-q|--quiet|--silent|--verbosity|-v|-vv|-vvv|-vvvv").unwrap();
+
+        // remove stdin since only the original process will process targets
+        // remove quiet and silent so we can force silent later to normalize output
+        let mut original = invocation
+            .filter(|s| !para_regex.is_match(s))
+            .collect::<Vec<String>>();
+
+        original.push("--silent".to_string()); // only output modifier allowed
+
+        // we need remove --parallel from command line so we don't hit this branch over and over
+        // but we must remove --parallel N manually; the filter above never sees --parallel and the
+        // value passed to it at the same time, so can't filter them out in one pass
+
+        // unwrap is fine, as it has to be in the args for us to be in this code branch
+        let parallel_index = original.iter().position(|s| *s == "--parallel").unwrap();
+
+        // remove --parallel
+        original.remove(parallel_index);
+
+        // remove N passed to --parallel (it's the same index again since everything shifts
+        // from removing --parallel)
+        original.remove(parallel_index);
+
+        // unvalidated targets fresh from stdin, just spawn children and let them do all checks
+        for target in targets {
+            // add the current target to the provided command
+            let mut cloned = original.clone();
+            cloned.push("-u".to_string());
+            cloned.push(target);
+
+            let bin = cloned.index(0).to_owned(); // user's path to feroxbuster
+            let args = cloned.index(1..).to_vec(); // and args
+
+            let permit = PARALLEL_LIMITER.acquire().await?;
+
+            log::debug!("parallel exec: {} {}", bin, args.join(" "));
+
+            tokio::task::spawn_blocking(move || {
+                let result = Command::new(bin)
+                    .args(&args)
+                    .spawn()
+                    .expect("failed to spawn a child process")
+                    .wait()
+                    .expect("child process errored during execution");
+
+                drop(permit);
+                result
+            });
+        }
+
+        clean_up(handles, tasks).await?;
+
+        log::trace!("exit: parallel branch && wrapped main");
+        return Ok(());
+    }
+
     if matches!(config.output_level, OutputLevel::Default) {
         // only print banner if output level is default (no banner on --quiet|--silent)
         let std_stderr = stderr(); // std::io::stderr

src/parser.rs

@@ -348,6 +348,14 @@ pub fn initialize() -> App<'static, 'static> {
                 .takes_value(true)
                 .help("Limit total number of concurrent scans (default: 0, i.e. no limit)")
         )
+        .arg(
+            Arg::with_name("parallel")
+                .long("parallel")
+                .value_name("PARALLEL_SCANS")
+                .takes_value(true)
+                .requires("stdin")
+                .help("Run parallel feroxbuster instances (one child process per url passed via stdin)")
+        )
         .arg(
             Arg::with_name("rate_limit")
                 .long("rate-limit")

src/scan_manager/tests.rs

@@ -383,7 +383,7 @@ fn feroxstates_feroxserialize_implementation() {
 
     let json_state = ferox_state.as_json().unwrap();
     let expected = format!(
-        r#"{{"scans":[{{"id":"{}","url":"https://spiritanimal.com","scan_type":"Directory","status":"NotStarted","num_requests":0}}],"config":{{"type":"configuration","wordlist":"/usr/share/seclists/Discovery/Web-Content/raft-medium-directories.txt","config":"","proxy":"","replay_proxy":"","target_url":"","status_codes":[200,204,301,302,307,308,401,403,405],"replay_codes":[200,204,301,302,307,308,401,403,405],"filter_status":[],"threads":50,"timeout":7,"verbosity":0,"silent":false,"quiet":false,"auto_bail":false,"auto_tune":false,"json":false,"output":"","debug_log":"","user_agent":"feroxbuster/{}","redirects":false,"insecure":false,"extensions":[],"headers":{{}},"queries":[],"no_recursion":false,"extract_links":false,"add_slash":false,"stdin":false,"depth":4,"scan_limit":0,"rate_limit":0,"filter_size":[],"filter_line_count":[],"filter_word_count":[],"filter_regex":[],"dont_filter":false,"resumed":false,"resume_from":"","save_state":false,"time_limit":"","filter_similar":[]}},"responses":[{{"type":"response","url":"https://nerdcore.com/css","path":"/css","wildcard":true,"status":301,"content_length":173,"line_count":10,"word_count":16,"headers":{{"server":"nginx/1.16.1"}}}}]"#,
+        r#"{{"scans":[{{"id":"{}","url":"https://spiritanimal.com","scan_type":"Directory","status":"NotStarted","num_requests":0}}],"config":{{"type":"configuration","wordlist":"/usr/share/seclists/Discovery/Web-Content/raft-medium-directories.txt","config":"","proxy":"","replay_proxy":"","target_url":"","status_codes":[200,204,301,302,307,308,401,403,405],"replay_codes":[200,204,301,302,307,308,401,403,405],"filter_status":[],"threads":50,"timeout":7,"verbosity":0,"silent":false,"quiet":false,"auto_bail":false,"auto_tune":false,"json":false,"output":"","debug_log":"","user_agent":"feroxbuster/{}","redirects":false,"insecure":false,"extensions":[],"headers":{{}},"queries":[],"no_recursion":false,"extract_links":false,"add_slash":false,"stdin":false,"depth":4,"scan_limit":0,"parallel":0,"rate_limit":0,"filter_size":[],"filter_line_count":[],"filter_word_count":[],"filter_regex":[],"dont_filter":false,"resumed":false,"resume_from":"","save_state":false,"time_limit":"","filter_similar":[]}},"responses":[{{"type":"response","url":"https://nerdcore.com/css","path":"/css","wildcard":true,"status":301,"content_length":173,"line_count":10,"word_count":16,"headers":{{"server":"nginx/1.16.1"}}}}]"#,
         saved_id, VERSION
     );
     println!("{}\n{}", expected, json_state);

tests/test_banner.rs

@@ -948,3 +948,27 @@ fn banner_doesnt_print_when_quiet() {
                 .and(predicate::str::contains("User-Agent").not()),
         );
 }
+
+#[test]
+/// test allows non-existent wordlist to trigger the banner printing to stderr
+/// expect to see nothing as --parallel forces --silent to be true
+fn banner_prints_parallel() {
+    Command::cargo_bin("feroxbuster")
+        .unwrap()
+        .arg("--stdin")
+        .arg("--parallel")
+        .arg("4316")
+        .assert()
+        .success()
+        .stderr(
+            predicate::str::contains("─┬─")
+                .not()
+                .and(predicate::str::contains("Target Url").not())
+                .and(predicate::str::contains("Parallel Scans").not())
+                .and(predicate::str::contains("Threads").not())
+                .and(predicate::str::contains("Wordlist").not())
+                .and(predicate::str::contains("Status Codes").not())
+                .and(predicate::str::contains("Timeout (secs)").not())
+                .and(predicate::str::contains("User-Agent").not()),
+        );
+}

tests/test_main.rs

@@ -1,8 +1,9 @@
 mod utils;
 use assert_cmd::Command;
 use httpmock::Method::GET;
-use httpmock::MockServer;
+use httpmock::{MockServer, Regex};
 use predicates::prelude::*;
+use std::fs::read_to_string;
 use utils::{setup_tmp_directory, teardown_tmp_directory};
 
 #[test]
@@ -89,3 +90,66 @@ fn main_use_empty_stdin_targets() -> Result<(), Box<dyn std::error::Error>> {
 
     Ok(())
 }
+
+#[test]
+/// send three targets over stdin, expect parallel to spawn children and each child config to show
+/// up in the output file
+fn main_parallel_spawns_children() -> Result<(), Box<dyn std::error::Error>> {
+    let t1 = MockServer::start();
+    let t2 = MockServer::start();
+    let t3 = MockServer::start();
+
+    let words = [
+        String::from("LICENSE"),
+        String::from("stuff"),
+        String::from("things"),
+        String::from("mostuff"),
+        String::from("mothings"),
+    ];
+    let (word_tmp_dir, wordlist) = setup_tmp_directory(&words, "wordlist")?;
+    let (output_dir, outfile) = setup_tmp_directory(&[], "output-file")?;
+    let (tgt_tmp_dir, targets) =
+        setup_tmp_directory(&[t1.url("/"), t2.url("/"), t3.url("/")], "targets")?;
+
+    Command::cargo_bin("feroxbuster")
+        .unwrap()
+        .arg("--stdin")
+        .arg("--parallel")
+        .arg("2")
+        .arg("-vvvv")
+        .arg("--debug-log")
+        .arg(outfile.as_os_str())
+        .arg("--wordlist")
+        .arg(wordlist.as_os_str())
+        .pipe_stdin(targets)
+        .unwrap()
+        .assert()
+        .success()
+        .stderr(
+            predicate::str::contains("Could not connect to any target provided")
+                .and(predicate::str::contains("Target Url"))
+                .not(), // no target url found
+        );
+
+    let contents = read_to_string(outfile).unwrap();
+    println!("contents: {}", contents);
+
+    assert!(contents.contains("parallel branch && wrapped main")); // exits parallel branch
+
+    // DBG      0.007 feroxbuster parallel exec: target/debug/feroxbuster
+    //   --debug-log /tmp/.tmpAjRts6/output-file --wordlist /tmp/.tmpS4CKKq/wordlist
+    //   --silent -u http://127.0.0.1:41979/
+    let r1 = Regex::new(&format!("parallel exec:.*-u {}", t1.url("/"))).unwrap();
+    let r2 = Regex::new(&format!("parallel exec:.*-u {}", t2.url("/"))).unwrap();
+    let r3 = Regex::new(&format!("parallel exec:.*-u {}", t3.url("/"))).unwrap();
+
+    assert!(r1.is_match(&contents)); // all 3 were spawned
+    assert!(r2.is_match(&contents));
+    assert!(r3.is_match(&contents));
+
+    teardown_tmp_directory(word_tmp_dir);
+    teardown_tmp_directory(tgt_tmp_dir);
+    teardown_tmp_directory(output_dir);
+
+    Ok(())
+}