dcc2

package

v0.643.0 Latest Latest Go to latest Published: Jun 9, 2026 License: AGPL-3.0 Imports: 10 Imported by: 0

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Valid go.mod file
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Repository

github.com/xunholy/promptzero

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Documentation ¶

Overview ¶

Package dcc2 implements Domain Cached Credentials v2 (DCC2 / MS-Cache v2 / mscash2, hashcat mode 2100): the format Windows (Vista / Server 2008+) uses to cache domain logons locally, dumped from a compromised workstation's SECURITY registry hive (HKLM\SECURITY\Cache, e.g. via impacket secretsdump). Unlike an NT hash a DCC2 cannot be passed-the-hash — it is an offline-crack- only credential — so the compute/verify side completes the credential toolkit: hash_identify recognises $DCC2$ (mode 2100) and hash_crack attacks it, but neither could produce or check one. Pure offline compute from operator-supplied strings; no network or device.

Algorithm ¶

DCC1 = MD4( MD4(password‖UTF-16LE) ‖ lower(username)‖UTF-16LE )   (= MS-Cache v1)
DCC2 = PBKDF2-HMAC-SHA1( DCC1, lower(username)‖UTF-16LE, iterations, 16 )

The username (lowercased, UTF-16LE) is the PBKDF2 salt; the default iteration count is 10240. The stored form is `$DCC2$<iterations>#<username>#<hex>`.

Wrap-vs-native judgement ¶

Native. It composes two in-tree primitives — internal/nthash.MD4 (the RFC-1320-verified MD4 behind nt_hash) and internal/wpa.PBKDF2 (the generic PBKDF2 behind pbkdf2_password / wpa_pmk_derive / postgres_scram) — plus UTF-16LE encoding. There is nothing to wrap; consistent with the other in-tree credential computes owning their crypto.

Verifiable / no confidently-wrong output ¶

Strongest verification class — gated byte-for-byte against the canonical hashcat mode-2100 example $DCC2$10240#tom#e4e938d12fe5974dc42a90120bd9c90f (password "hashcat"), the independent anchor, plus pycryptodome-confirmed vectors. A malformed hash (wrong prefix / field count / iteration count / non-hex) is rejected with an error, never silently "verified".

Index ¶

func Compute(username, password string, iterations int) (string, error)
type Parsed
- func Parse(s string) (*Parsed, error)
type Result
- func Verify(password, hash string) (*Result, error)

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

func Compute ¶

func Compute(username, password string, iterations int) (string, error)

Compute returns the DCC2 stored value for (username, password). iterations <= 0 selects the default of 10240.

Types ¶

type Parsed ¶

type Parsed struct {
	Iterations int
	Username   string
	Hash       string // 32 lowercase hex chars
}

Parsed is a decomposed DCC2 hash.

func Parse ¶

func Parse(s string) (*Parsed, error)

Parse decomposes a `$DCC2$<iterations>#<username>#<hex>` string.

type Result ¶

type Result struct {
	Matched    bool   `json:"matched"`
	Username   string `json:"username"`
	Iterations int    `json:"iterations"`
}

Result is the outcome of verifying a candidate password.

func Verify ¶

func Verify(password, hash string) (*Result, error)

Verify reports whether password produces the given $DCC2$ hash (the username and iteration count are taken from the hash). Compared constant-time.

Source Files ¶

View all Source files

dcc2.go

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