Search all PE files in a directory for ones which import a specific DLL

FindTargetImports.cs

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using PeNet;
using PeNet.Header.Pe;

namespace FindTargetImports
{
    class Program
    {
        public static readonly string Usage = "FindTargetImports.exe <search_root> <target_module.dll>";

        static void Main(string[] args)
        {
            if (args.Length < 2)
            {
                Console.WriteLine(Usage);
                return;
            }
            string directory = args[0];
            string targetDll = args[1];
            if (!Directory.Exists(directory))
            {
                Console.WriteLine("[-] Couldn't find the target directory");
                return;
            }

            Console.WriteLine();
            Stopwatch timer = Stopwatch.StartNew();

            List<string> extensions = new List<string> { "exe", "dll", "sys" };
            // Get all files in the target directory without recursing
            IEnumerable<string> allFiles = Directory.EnumerateFiles(directory, "*.*", SearchOption.TopDirectoryOnly)
                .Where(s => extensions.Contains(Path.GetExtension(s).TrimStart('.').ToLowerInvariant()));

            // Thread-safe collection just in case
            ConcurrentBag<string> matches = new ConcurrentBag<string>();
            // Parallelize our search 
            Parallel.ForEach(allFiles, file =>
            {
                if (ParseImportedModulesForMatch(file, targetDll))
                {
                    matches.Add(file);
                }
            });


            // Print out final results
            if (matches.Count > 0)
            {
                foreach (string match in matches.Distinct())
                {
                    Console.WriteLine($"[+] {match} imports {args[1]}");
                }
            }
            else
            {
                Console.WriteLine("[-] No results found");
            }

            timer.Stop();
            Console.WriteLine($"\nCompleted execution in {timer.ElapsedMilliseconds}ms");

        }

        private static bool ParseImportedModulesForMatch(string filePath, string targetImport)
        {
            try
            {
                PeFile peHeader = new PeFile(File.ReadAllBytes(filePath));

                ImportFunction[] imports = peHeader.ImportedFunctions;
    
                foreach (ImportFunction import in imports)
                {
                    if (import.DLL.ToLower() == targetImport)
                    {
                        return true;
                    }
                }
            }
            catch { }

            return false;
        }
    }
}