Unpack [portable] | Deepsea Obfuscator V4

I notice you're asking about "DeepSea Obfuscator v4 unpack" — specifically looking for the unpacking feature of this obfuscator.

Here's a concise breakdown:

Phase 1: Bypassing the Native Stub

Most DeepSea v4 samples are packaged as a native executable (C/C++ launcher) that writes the .NET assembly into memory. deepsea obfuscator v4 unpack

1. Load the sample into x64dbg (if native) or directly into dnSpy if it loads.
2. Set a breakpoint on kernel32!VirtualAlloc and kernel32!WriteProcessMemory.
3. Run the binary. It will allocate a buffer and write the decrypted PE image.
4. Once the buffer is written, dump the memory region using scyllaHide or manually.

Alternatively: If the file runs as a pure .NET assembly (managed entrypoint), launch dnSpy, attach to the process immediately after startup, and pause execution.

Phase 3: De-virtualization with Modified de4dot

Standard de4dot (v3.2) will fail with:

Unknown obfuscator: DeepSea (Unsupported version 4.0)

You need a forked version with DeepSeaObfuscator v4 support. The logic in this fork does the following: I notice you're asking about "DeepSea Obfuscator v4

# Pseudo-logic of a working de4dot v4 patch
if detect_deepsea_v4(module):
    fix_virtual_calls(module)  # Replaces VM dispatch with direct calls
    decrypt_strings_via_simulation(module) # Emulates the delegate builder
    restore_cfg(module)        # Rebuilds switch-based CFG into if/else

Run:

de4dot_modified.exe target_dump.exe --dont-rename --keep-types

The --dont-rename flag is crucial because the original Unicode mangled names often cause de4dot to crash. You will rename manually later. Load the sample into x64dbg (if native) or

1.2 Dynamic String Decryption via Delegates

Strings are never stored in plaintext. Instead, they are stored as encrypted byte arrays. At runtime, a delegate is generated via System.Reflection.Emit to decrypt them just in time. The decryption key is often derived from the current method token or timestamp, making static extraction nearly impossible.