This class handles the download process, injecting a verification step before saving the file to disk.
using System;
using System.IO;
using System.Net.Http;
using System.Security.Cryptography;
using System.Threading.Tasks;
namespace ModManager.Core.Features
public class CurseVerifier
private readonly HttpClient _httpClient;
public CurseVerifier(HttpClient httpClient)
_httpClient = httpClient;
/// <summary>
/// Downloads a file and verifies its integrity using SHA1 hash.
/// </summary>
/// <param name="downloadUrl">The direct download URL from CurseForge CDN.</param>
/// <param name="expectedHash">The SHA1 hash provided by the CurseForge API.</param>
/// <param name="destinationPath">Local path to save the file.</param>
public async Task<VerificationResult> DownloadAndVerifyAsync(string downloadUrl, string expectedHash, string destinationPath)
try
// 1. Download the file stream
var response = await _httpClient.GetAsync(downloadUrl, HttpCompletionOption.ResponseHeadersRead);
response.EnsureSuccessStatusCode();
using (var stream = await response.Content.ReadAsStreamAsync())
using (var fileStream = File.Create(destinationPath))
using (var sha1 = SHA1.Create())
// We use a custom stream wrapper to hash while downloading to avoid reading the file twice
var hashingStream = new HashingStream(stream, sha1);
await hashingStream.CopyToAsync(fileStream);
// 2. Compute the final hash
string actualHash = hashingStream.GetHashAsString();
// 3. Verify
if (!string.Equals(actualHash, expectedHash, StringComparison.OrdinalIgnoreCase))
// Verification Failed: Delete the corrupted file
fileStream.Close();
File.Delete(destinationPath);
return new VerificationResult
Success = false,
Error = "Hash Mismatch",
Details = $"Expected: expectedHash, Actual: actualHash"
;
return new VerificationResult Success = true ;
catch (Exception ex)
// Clean up partial file if exists
if (File.Exists(destinationPath)) File.Delete(destinationPath);
return new VerificationResult Success = false, Error = ex.Message ;
// Helper stream to calculate hash on-the-fly
public class HashingStream : Stream
private readonly Stream _baseStream;
private readonly SHA1 _sha1;
private byte[] _hash;
public HashingStream(Stream baseStream, SHA1 sha1)
_baseStream = baseStream;
_sha1 = sha1;
public override int Read(byte[] buffer, int offset, int count)
int bytesRead = _baseStream.Read(buffer, offset, count);
if (bytesRead > 0)
_sha1.TransformBlock(buffer, offset, bytesRead, buffer, offset);
return bytesRead;
public string GetHashAsString()
if (_hash == null)
_sha1.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
_hash = _sha1.Hash;
return BitConverter.ToString(_hash).Replace("-", "").ToLowerInvariant();
// Standard Stream overrides
public override bool CanRead => _baseStream.CanRead;
public override bool CanSeek => false;
public override bool CanWrite => false;
public override long Length => _baseStream.Length;
public override long Position get => _baseStream.Position; set => throw new NotSupportedException();
public override void Flush() => _baseStream.Flush();
public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
public override void SetLength(long value) => throw new NotSupportedException();
public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
public class VerificationResult
public bool Success get; set;
public string Error get; set;
public string Details get; set;
This shows how you would call the verifier within your existing download logic.
public async Task InstallMod(CurseModFile modFile)
string downloadUrl = modFile.DownloadUrl;
string expectedFingerprint = modFile.Hash; // Assuming this comes from API
string fileName = modFile.FileName;
string installPath = Path.Combine(_modsFolder, fileName);
Console.WriteLine($"Starting verified download for: fileName...");
var verifier = new CurseVerifier(_httpClient);
var result = await verifier.DownloadAndVerifyAsync(downloadUrl, expectedFingerprint, installPath);
if (result.Success)
Console.WriteLine("✅ Download Verified Successfully.");
// Trigger UI update or completion event
else
Console.WriteLine($"❌ Verification Failed: result.Error");
Console.WriteLine($"Details: result.Details");
// Alert user to retry or check connection
Incident ID: IR-2026-001
Date: April 9, 2026
Reported by: Automated detection / Security team cause curse download verified
The most common payload. You run "Cause_Setup_Verified.exe," and within seconds, a script scrapes your browser’s saved passwords, cookies, and crypto wallets. Your Discord token is stolen, and your account is used to spread the same malicious link to your friends.
If you're looking for information or reports on curses from an academic or informational standpoint: This class handles the download process, injecting a
Beyond malware, there are two other reasons to avoid the "cause curse download verified" path: legality and ethics.
Despite available verification tools, many users skip them. Reasons include: This shows how you would call the verifier
Attackers count on these behavioral gaps. The curse is not a technical failure; it is a human one.