ACE file signature
Magic number at offset 7 · **ACE**
A WinAce archive carries the ASCII marker **ACE** at byte offset 7, after the header's checksum, size and type fields. It is one of the few common signatures that does not sit at the start of the file.
What this magic number means
A magic number is a short, fixed run of bytes at a known position that tells a program what a file really is, no matter what the filename says. If a file contains, at offset 7, the bytes 2A 2A 41 43 45 2A 2A (the text **ACE**), it is a ACE file.
The format is best known today for CVE-2018-20250, the unacev2.dll path-traversal flaw that led WinRAR to drop ACE support entirely, so extract old .ace archives only with maintained tools.
Formats that use the 2A 2A 41 43 signature
These file types in our database carry this signature:
How to check a file's signature
You can read the first bytes of any file yourself. The magic bytes are shown in hex, the same way this page lists them.
Linux & macOS
- xxd -s 7 -l 7 example.ace
- hexdump -C -s 7 -n 7 example.ace
- file example.ace
Windows (PowerShell)
- Format-Hex -Path example.ace -Count 16
Python
- f=open("example.ace","rb");f.seek(7);f.read(7).hex()
In your browser
- Drop the file into the WhatFileType identifier, which reads the signature without uploading it.
Frequently asked questions
What is the ACE file signature?
ACE files carry, at offset 7, the hex bytes 2A 2A 41 43 45 2A 2A (**ACE** in ASCII). This magic number identifies the format regardless of the file's name or extension.
How do I check a file's magic number?
Open the file in a hex editor, or run a command such as xxd -l 16 example.ace on Linux or macOS, or Format-Hex -Path example.ace -Count 16 in Windows PowerShell, and read the first bytes.
Can a file fake the ACE signature?
Renaming a file does not change its bytes, so the extension can lie but the signature usually cannot. A genuine ACE file has these exact bytes; a file with the wrong bytes is not really ACE, whatever its name says.