[SunHELP] unsupported compression method 99

Martin Frost martin at omniconsumerproducts.com
Wed Dec 19 15:10:20 CST 2007

On Wed, 19 Dec 2007, Rodney Sparapani wrote:

> I have been having a problem unzip'ing password protected zip files from
> Windows users with the error message: unsupported compression method 99

> Maybe others already know about this, but
> it has only been recently that unzip stopped working for us, perhaps due
> to a change in Windows?

The method for password-protecting Zip files changed a couple of years 
ago. The old encryption method was too easy to brute-force on modern 
hardware. I believe it now uses AES.

Could it be that your users have finally upgraded from the old vulnerable 


More information about the SunHELP mailing list