Microsoft MSTSC(RDP-File) Hash

What is Microsoft MSTSC(RDP-File)?

The Microsoft MSTSC (Remote Desktop Protocol) credential file format, commonly referred to as an RDP-file or ".rdp" credential cache, is not a cryptographic hash algorithm per se but rather a proprietary binary format used to store encrypted credentials (username/password) for automated remote desktop connections. Originating from Microsoft’s Terminal Services architecture (now part of Windows Remote Desktop), this format emerged in the late 1990s to facilitate secure credential persistence for scripted or unattended logins. Structurally, the RDP-file encodes credentials using a custom encryption scheme tied to the client’s machine-specific key derived from the Windows Data Protection API (DPAPI), combined with a symmetric cipher (historically RC4 in older versions, later upgraded to AES in modern iterations). The format lacks a standardized hash function but instead relies on DPAPI’s per-machine encryption keys, which are tied to the user’s SID and machine account credentials, making it inherently tied to Windows domain environments. Its primary use-case is enabling automated, secure remote sessions without manual password prompts, though it is often mislabeled as a "hash" due to its role in credential storage rather than direct cryptographic hashing.

The vulnerability of this format to cracking stems from fundamental design flaws and exploitability of its underlying cryptographic assumptions. The original implementation (pre-Windows 10) relied on DPAPI’s machine-wide encryption keys, which are vulnerable to offline attacks if an attacker gains access to the target machine or its backup files (e.g., via stolen backups or lateral movement in a domain). The lack of a salt or iterative hashing mechanism in credential storage exacerbates this, as passwords are encrypted symmetrically rather than hashed with a work-factor (e.g., PBKDF2 or Argon2). Additionally, modern GPU-accelerated cracking tools (e.g., Hashcat) can efficiently brute-force or dictionary-attack the encrypted credentials by leveraging parallelized decryption attempts against the DPAPI keys, especially if the password meets weak complexity requirements. Furthermore, the format’s reliance on machine-specific keys means that once a single machine’s DPAPI key is compromised—whether via malware (e.g., Pass-the-Hash attacks) or physical access—all stored RDP credentials become trivially recoverable. Post-2018 updates introduced AES-256 and per-user encryption keys, but legacy systems and improperly configured DPAPI contexts remain vulnerable to credential dumping via tools like Mimikatz or credential extraction from memory.

Identifying Microsoft MSTSC(RDP-File) Hashes

Identifying a hash blindly is often difficult because multiple algorithms can output strings of the exact same length. For example, a standard 32-character hexadecimal string could be MD5, NTLM, MD4, or LM. To definitively identify Microsoft MSTSC(RDP-File), security researchers analyze the hash against a strict regular expression (regex) signature (shown above) to find structural matches.

How to Crack Microsoft MSTSC(RDP-File)

If you need to recover the plaintext password for a Microsoft MSTSC(RDP-File) hash during a penetration test or forensics investigation, you must supply the correct module ID to your cracking software. Use the exact commands provided at the top of this page to target the hash successfully.