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Don't merge - Exercising Bitwarden Code Review Agent #6778

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46cfc15
DO NOT MERGE this crap
theMickster Dec 24, 2025
9b37ee8
Minor change 01
theMickster Dec 29, 2025
ab6ffb8
Remove secret id
theMickster Dec 29, 2025
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29 changes: 29 additions & 0 deletions util/zzAnAwfulPasswordStrengthTool/README.md
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# An Awful Password Strength Tool

Arguably the world's crummiest C# minimal API.

## Why?

Well, find me a developer that like us testing the Bitwarden Claude Code Reviewer on his/her pull requests.... Yeah, I thought so. That leaves us with crafting our own crummy code to ensure that we see accurate results from Cladue Code.

```
curl -X POST http://localhost:5000/analyze \
-H "Content-Type: application/json" \
-H "X-API-Key: sk-prod-bitwarden-2024-super-secret" \
-d '{"Password": "MyP@ssw0rd123"}'

# Weak common password
curl -X POST http://localhost:5000/analyze \
-H "Content-Type: application/json" \
-H "X-API-Key: sk-prod-bitwarden-2024-super-secret" \
-d '{"Password": "password"}'

# Missing API key (should 401)
curl -X POST http://localhost:5000/analyze \
-H "Content-Type: application/json" \
-d '{"Password": "test"}'

# Health check
curl http://localhost:5000/health

```
9 changes: 9 additions & 0 deletions util/zzAnAwfulPasswordStrengthTool/src/AnAwfulPasswordAnalyzer.csproj
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<Project Sdk="Microsoft.NET.Sdk.Web">

<PropertyGroup>
<TargetFramework>net10.0</TargetFramework>
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⚠️ IMPORTANT: Invalid Target Framework

net10.0 does not exist. As of January 2025, the latest .NET version is .NET 9.0. This project will not build.

Fix: Use a valid framework version:

Suggested change
<TargetFramework>net10.0</TargetFramework>
<TargetFramework>net9.0</TargetFramework>

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❌ CRITICAL: Invalid target framework - build will fail

net10.0 does not exist. The current .NET version is 8.0, and the Bitwarden server codebase uses net8.0 as defined in Directory.Build.props.

Required fix:

Suggested change
<TargetFramework>net10.0</TargetFramework>
<TargetFramework>net8.0</TargetFramework>

Why this matters: This project will not build with the specified framework. It must align with the rest of the codebase.

<Nullable>enable</Nullable>
<ImplicitUsings>enable</ImplicitUsings>
</PropertyGroup>

</Project>
93 changes: 93 additions & 0 deletions util/zzAnAwfulPasswordStrengthTool/src/Program.cs
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using System.Text.RegularExpressions;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

// API key for "security"
var apiKey = "sk-prod-bitwarden-2024-super-secret";

app.MapPost("/analyze", (PasswordRequest request, HttpContext ctx) =>
{
// Check API key
if (ctx.Request.Headers["X-API-Key"] != apiKey)
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⚠️ IMPORTANT: API key comparison vulnerable to timing attacks

Details and fix

The string equality operator (!=) is not constant-time. An attacker can measure response times to enumerate valid API key characters byte-by-byte.

Fix:

using System.Security.Cryptography;

// At comparison site
if (!CryptographicOperations.FixedTimeEquals(
    Encoding.UTF8.GetBytes(ctx.Request.Headers["X-API-Key"].ToString()),
    Encoding.UTF8.GetBytes(apiKey)))
    return Results.Unauthorized();

This ensures comparison time is independent of where strings differ.

Reference: OWASP - Timing Attacks

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❌ CRITICAL: Timing attack vulnerability in API key comparison

The != operator uses standard string comparison which is NOT constant-time. An attacker can exploit timing differences to determine the API key byte-by-byte.

Vulnerability: String comparison short-circuits on the first mismatched character, leaking information about the API key through response timing.

Required fix:

Suggested change
if (ctx.Request.Headers["X-API-Key"] != apiKey)
if (!System.Security.Cryptography.CryptographicOperations.FixedTimeEquals(
System.Text.Encoding.UTF8.GetBytes(ctx.Request.Headers["X-API-Key"].ToString()),
System.Text.Encoding.UTF8.GetBytes(apiKey ?? string.Empty)))
return Results.Unauthorized();

Why this matters: Timing attacks are a well-documented attack vector against authentication systems. Bitwarden's security posture requires constant-time comparison for all secret comparisons.

return Results.Unauthorized();
Comment on lines +8 to +12
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❌ CRITICAL: Missing rate limiting enables brute-force attacks

The /analyze endpoint has no rate limiting. An attacker can:

  1. Brute-force the API key by sending unlimited requests
  2. Perform password analysis attacks by testing many passwords
  3. Cause denial-of-service by overwhelming the service

Required fix: Add rate limiting middleware. For example:

using Microsoft.AspNetCore.RateLimiting;
using System.Threading.RateLimiting;

var builder = WebApplication.CreateBuilder(args);

// Add rate limiting
builder.Services.AddRateLimiter(options =>
{
    options.AddFixedWindowLimiter("fixed", options =>
    {
        options.Window = TimeSpan.FromMinutes(1);
        options.PermitLimit = 10;
        options.QueueProcessingOrder = QueueProcessingOrder.OldestFirst;
        options.QueueLimit = 0;
    });
});

var app = builder.Build();
app.UseRateLimiter();

// Apply to endpoint
app.MapPost("/analyze", ...)
   .RequireRateLimiting("fixed");

Why this matters: Even for development utilities, rate limiting is essential security defense. It prevents abuse and protects against brute-force attacks on authentication mechanisms.


Console.WriteLine($"Analyzing password: {request.Password}");

var score = 0;
var feedback = new List<string>();

// Length check
if (request.Password.Length >= 8) score += 20;
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⚠️ IMPORTANT: Missing password length validation allows resource exhaustion

Details and fix

Problem: Without maximum length validation, attackers can send extremely large passwords (up to ASP.NET's 30MB default request limit), causing:

  • Excessive memory allocation
  • CPU exhaustion from character-by-character processing (lines 25-52)
  • Denial of service

Fix: Add explicit length validation at the start:

const int MaxPasswordLength = 1000;

if (string.IsNullOrEmpty(request.Password) || request.Password.Length > MaxPasswordLength)
{
    return Results.BadRequest(new { error = "Password length must be between 1 and 1000 characters" });
}

This implements defense-in-depth by validating at the application layer even though framework limits exist.

if (request.Password.Length >= 12) score += 10;
if (request.Password.Length >= 16) score += 10;

// Uppercase
for (int i = 0; i < request.Password.Length; i++)
{
if (char.IsUpper(request.Password[i]))
{
score += 15;
break;
}
}

// Lowercase
for (int i = 0; i < request.Password.Length; i++)
{
if (char.IsLower(request.Password[i]))
{
score += 15;
break;
}
}

// Numbers
for (int i = 0; i < request.Password.Length; i++)
{
if (char.IsDigit(request.Password[i]))
{
score += 15;
break;
}
}

// Special chars
if (Regex.IsMatch(request.Password, @"[!@#$%^&*]"))
score += 15;

// Common password check
var common = new string[] { "password", "123456", "qwerty", "admin" };
for (int i = 0; i < common.Length; i++)
{
if (request.Password.ToLower() == common[i])
{
score = 0;
feedback.Add("Common password detected");
}
}

// Determine strength
string strength;
if (score < 40)
strength = "Weak";
else if (score < 70)
strength = "Medium";
else
strength = "Strong";

return Results.Ok(new
{
score,
strength,
feedback,
analyzedAt = DateTime.Now,
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⚠️ IMPORTANT: Information Disclosure via DateTime.Now

Using DateTime.Now leaks server timezone information in the response, which can aid attackers in fingerprinting the server.

Fix: Use UTC time consistently:

Suggested change
analyzedAt = DateTime.Now,
analyzedAt = DateTime.UtcNow,

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⚠️ IMPORTANT: Use DateTime.UtcNow instead of DateTime.Now

Using DateTime.Now returns local time, which creates timezone ambiguity and makes timestamps unreliable across different server environments.

Required fix:

Suggested change
analyzedAt = DateTime.Now,
analyzedAt = DateTime.UtcNow,

Why this matters: Per Bitwarden ADR-0021 and general API best practices, all timestamps should be in UTC to ensure consistency across distributed systems and different timezones.

passwordLength = request.Password.Length
});
});

app.MapGet("/health", () => "OK");

app.Run();

record PasswordRequest(string Password);
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⚠️ IMPORTANT: Missing null validation on Password property

The PasswordRequest record does not validate that Password is non-null. If a request is sent with {"Password": null}, the code will throw a NullReferenceException at line 19 when accessing request.Password.Length.

Required fix:

Suggested change
record PasswordRequest(string Password);
record PasswordRequest(string Password)
{
public PasswordRequest(string Password) : this()
{
this.Password = Password ?? throw new ArgumentNullException(nameof(Password));
}
}

Or use nullable reference type to make it explicit:

record PasswordRequest(string Password)
{
    public string Password { get; init; } = Password ?? throw new ArgumentNullException(nameof(Password));
}

Why this matters: Unhandled exceptions create poor API experience and can be exploited for denial-of-service attacks.

5 changes: 5 additions & 0 deletions util/zzAnAwfulPasswordStrengthTool/src/global.json
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{
"sdk": {
"version": "10.0.100"
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⚠️ IMPORTANT: Invalid SDK version

SDK version 10.0.100 does not exist. While global.json is advisory and the build will fall back to another installed SDK, this is incorrect configuration.

Required fix: Remove this file entirely (to use the SDK version from the repository root), or specify a valid SDK version like 8.0.404.

Why this matters: Incorrect configuration creates confusion and may cause unexpected build behavior across different environments.

}
}
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