Re: [websec] default value for max-age ? (was: Re: Strict-Transport-Security syntax redux)

Yoav Nir <> Tue, 03 January 2012 06:26 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 1ED9621F8560 for <>; Mon, 2 Jan 2012 22:26:43 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -10.549
X-Spam-Status: No, score=-10.549 tagged_above=-999 required=5 tests=[AWL=0.050, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id ugJcJLaBgMOM for <>; Mon, 2 Jan 2012 22:26:42 -0800 (PST)
Received: from ( []) by (Postfix) with ESMTP id C96F521F84B2 for <>; Mon, 2 Jan 2012 22:26:41 -0800 (PST)
X-CheckPoint: {4F029D72-0-1B221DC2-1FFFF}
Received: from ( []) by (8.13.8/8.13.8) with ESMTP id q036Qd4F019071; Tue, 3 Jan 2012 08:26:39 +0200
Received: from ([]) by ([]) with mapi; Tue, 3 Jan 2012 08:26:38 +0200
From: Yoav Nir <>
To: =JeffH <>
Date: Tue, 3 Jan 2012 08:26:36 +0200
Thread-Topic: [websec] default value for max-age ? (was: Re: Strict-Transport-Security syntax redux)
Thread-Index: AczJ4KW7YBXce8SdTxWBYxcMVLRlug==
Message-ID: <>
References: <>
In-Reply-To: <>
Accept-Language: en-US
Content-Language: en-US
acceptlanguage: en-US
x-kse-antivirus-interceptor-info: scan successful
x-kse-antivirus-info: Clean
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Cc: IETF WebSec WG <>
Subject: Re: [websec] default value for max-age ? (was: Re: Strict-Transport-Security syntax redux)
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Web Application Security Minus Authentication and Transport <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 03 Jan 2012 06:26:43 -0000

On Jan 3, 2012, at 1:29 AM, =JeffH wrote:

> Julian wondered..
>> wouldn't it make sense to have a default for max-age so it
>> can be made OPTIONAL?
> hm ... I lean towards keeping max-age as REQUIRED (without a default value) and 
> thus hopefully encouraging deployers to think a bit about this and its 
> ramifications, and also because its value is so site-specific in terms of a web 
> application's needs, deployment approach, and tolerance for downside risk of 
> breaking itself.

I tend to agree, but it's not deployers who are going to do the thinking - it's the implementers of web servers. 

So somewhere, in some control panel for IIS, or a config file for Apache, or some WebUI for some SSL-VPN, there's going to be a configuration to turn on HSTS, and that product is going to have a default max-age. The deployers are just going to check the box.

I think we should provide guidance for those implementers as to what is a good default there.