[Owasp-leaders] HTML Security Annotations

Dinis Cruz dinis.cruz at owasp.org
Wed Jan 4 18:26:01 UTC 2017

Hi Kevin, I view this annotations useful for the cases where the issue
either known (and marked as 'no fix'/'risk-accepted') or a true false

for example I've seen shopping cards solutions that 'by design' and 'on
purpose' allow CSRF to add items to the basket (they are used by 3rd party
integrations). In this case there are other mitigation controls and the
risk has been understood and accepted by the customer/client

Does that make sense?


On 4 January 2017 at 18:12, Kevin W. Wall <kevin.w.wall at gmail.com> wrote:

> Overall, I am supportive of developers adding hints to tools that
> something *should* be in place, like a anti-CRSF token, an HSTS or CSP
> header should be used here, etc. Not as mich for something not being needed.
> Maybe I am missing something here, but I am very uncomfortable in having
> developers indicate that some tool should blindly accept that they know
> better and not flag (say) a CSRF vulnerability because they have marked a
> form "data-no-csrf". This is like saying "Trust me, I know what I'm doing".
> They may, but they may not, so if ZAP or some other tool decides that a
> security analyst doesn't really need to see an potential issue because some
> developer says "move along, move along; nothing to see here", to me that is
> tantamount to putting the fox in charge of guarding the henhouse. I can see
> the value of when devs are running SAST or DAST tools against their own
> code, but not when an independent security analyst is doing this
> validation. Then I want to see everything.
> -kevin
> --
> Blog: http://off-the-wall-security.blogspot.com/.   | Twitter: @KevinWWall
> NSA: All your crypto bit are belong to us.
> On Jan 4, 2017 12:25 PM, "Dinis Cruz" <dinis.cruz at owasp.org> wrote:
>> Thinking about this a bit more, isn't what we saying this: *"Form is
>> vulnerable to CSRF which is an accepted risk (**so tools please don't
>> report this finding)**" *
>> Of course that this needs to be followed up internally and the awareness
>> of this issue must be known (and risk accepted). Ideally, there should be
>> (passing tests) that prove the exploitability and confirm it's non-impact
>> status (ZAP could be used for this)
>> This is very powerful since it allows the tools to become much more
>> clever and to react to information provided by the app.
>> Note the we can also use this annotations the other *"Form should be
>> protected to CRSF" , "CSP should be in place", "HSTS header should exist",
>> "Server side validation should match client side validation", "this field
>> is a asset (credit card)", "this field should not be an predictable direct
>> object reference" etc...*
>> Some of these mappings could also be provided via source code analysis or
>> mappings (exposed to the tools)
>> What is very important for this to work is the speed of CI loop (so that
>> a code change, lets to very quick tool results)
>> Dinis
>> On 4 January 2017 at 15:50, psiinon <psiinon at gmail.com> wrote:
>>> Replying inline to Dave's comments to me and Dinis publicly with his
>>> blessing ;)
>>> On Wed, Jan 4, 2017 at 2:46 PM, Dave Wichers <dave.wichers at owasp.org>
>>> wrote:
>>>> Simon,
>>>> I like these ideas but I've had resistance to code annotations that are
>>>> tool specific. i.e., to them they just clutter the code unnecessary.
>>>> (e.g., SonarQube specific ignore warnings notations).
>>> I'm hoping these can be cross tool, but no idea if that will actually
>>> happen ;)
>>> For info Ferruh Mavituna (Netsparker CEO) has replied to my tweet and
>>> seems broadly supportive;) https://twitter.com/fmavituna/
>>> status/816669797811441664
>>>> However, for your example does it do both of these things? Or just the
>>>> first:
>>>> 1) It tells the auditor CSRF isn't necessary. (As you've said)
>>>> 2) Does it actually tell some control to NOT enforce CSRF on this form?
>>>> i.e., without this annotation, it WOULD be protected from CSRF?
>>>> If it does #2 then its not just a 'note' its actually part of the
>>>> configuration and as such they of course can't complain about using it. I
>>>> suspect it doesn't do #2. Assuming that is correct is there any way to
>>>> correlate these annotations with the configuration to make sure there
>>>> aren't any mismatches? I.e., no-CSRF note in HTML when its actually ON, or
>>>> vice versa?
>>> I envisioned it as a note rather than something that _had_ to be acted
>>> upon (ie #1)
>>> If an auditor (or tool) found a form with this annotation _and_ an anti
>>> CSRF token then I think they should flag that as a real problem. I'll
>>> certainly do that in ZAP:)
>>> In order to prevent CSRF tokens from having any affect if the annotation
>>> was supplied then we'd have to change every application/framework that
>>> implemented CSRF tokens. I dont see that happening;)
>>> Cheers,
>>> Simon
>>>> -Dave
>>>> On Wed, Jan 4, 2017 at 9:15 AM, psiinon <psiinon at gmail.com> wrote:
>>>>> OK, so I did initially call it data-security=”no-csrf” :)
>>>>> I'm happy to go with the consensus...
>>>>> On Wed, Jan 4, 2017 at 2:12 PM, Dinis Cruz <dinis.cruz at owasp.org>
>>>>> wrote:
>>>>>> This is a brilliant idea, but I would make it a name-value pair
>>>>>> (easier to parse and more future proof)
>>>>>> On 4 Jan 2017 1:56 p.m., "psiinon" <psiinon at gmail.com> wrote:
>>>>>> Leaders,
>>>>>> All security tools suffer from false positives (FP’s), and good tools
>>>>>> allow these FPs to be flagged in the tool. SAST tools also typically allow
>>>>>> the source code to be annotated to prevent FPs from being flagged, eg the
>>>>>> @SuppressWarnings annotation in Java.
>>>>>> I've discussed this with Mozilla web developers and we have decided
>>>>>> to start using what I've dubbed 'HTML security annotations'.
>>>>>> The first one we will be using is to allow forms to be flagged as not
>>>>>> requiring (anti) CSRF tokens, eg
>>>>>> <form action="/my-handling-form-page" method="post" data-no-csrf>
>>>>>>     <div>
>>>>>>         <label for="search">Search:</label>
>>>>>>         <input type="text" id=”search" />
>>>>>>     </div>
>>>>>> </form>
>>>>>> The 'data-no-csrf' attribute is an indication that the developers
>>>>>> know all about CSRF tokens and have decided that this form doesnt require
>>>>>> one.
>>>>>> Security tools _can_ choose to not flag such forms as being insecure
>>>>>> because they dont have a CSRF token. They can also make it easier for their
>>>>>> users to find all forms that so have such tokens:)
>>>>>> Theres no guarantee that the developers are right, so a sensible
>>>>>> pentester would not place too much faith in this attributes use.
>>>>>> However its an easy and effective way to reduce FPs in DAST tools and
>>>>>> also an easy way to indicate to bug bounty participants that they should
>>>>>> only report these forms if they are _really_ sure they can be usefully
>>>>>> exploited.
>>>>>> There are other alternative solutions to this particular problem,
>>>>>> including:
>>>>>>    1. Adding CSRF tokens to all forms whether they need it or not.
>>>>>>    That feels nasty to me and I'm not going to suggest it to our devs ;)
>>>>>>    2. Having tool specific configurations for flagging FPs. Many
>>>>>>    tools support this but personally I like the annotation approach that can
>>>>>>    be adopted by all tools
>>>>>> So thats the first one we're trying out, and I can see the potential
>>>>>> for more of them.
>>>>>> What do you think?
>>>>>> If everyone else hates this idea then we can keep as Mozilla
>>>>>> specific. However if there is broad support for this them maybe it could be
>>>>>> mentioned on the relevant pages of the OWASP wiki.
>>>>>> In any case I'll be adding the option to ignore forms flagged in this
>>>>>> way to ZAP ;)
>>>>>> All constructive feedback appreciated, including suggestions for
>>>>>> other annotations that could be useful.
>>>>>> Cheers,
>>>>>> Simon
>>>>>> --
>>>>>> OWASP ZAP <https://www.owasp.org/index.php/ZAP> Project leader
>>>>>> _______________________________________________
>>>>>> OWASP-Leaders mailing list
>>>>>> OWASP-Leaders at lists.owasp.org
>>>>>> https://lists.owasp.org/mailman/listinfo/owasp-leaders
>>>>> --
>>>>> OWASP ZAP <https://www.owasp.org/index.php/ZAP> Project leader
>>>>> _______________________________________________
>>>>> OWASP-Leaders mailing list
>>>>> OWASP-Leaders at lists.owasp.org
>>>>> https://lists.owasp.org/mailman/listinfo/owasp-leaders
>>> --
>>> OWASP ZAP <https://www.owasp.org/index.php/ZAP> Project leader
>> _______________________________________________
>> OWASP-Leaders mailing list
>> OWASP-Leaders at lists.owasp.org
>> https://lists.owasp.org/mailman/listinfo/owasp-leaders
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.owasp.org/pipermail/owasp-leaders/attachments/20170104/bc7df5d3/attachment.html>

More information about the OWASP-Leaders mailing list