Hi Linda,

Thanks for your SECDIR review of the document. And thank you for jumping on the 
request to provide the review. Much appreciated.

I do have a few comments. Please see inline.

> On Jan 29, 2025, at 10:39 AM, Linda Dunbar <[email protected]> wrote:
> 
> Med, 
>  
> You are right that  the risks associated with ACL manipulation are not unique 
> to this draft and align with those in RFC 8519. However, the introduction of 
> new features such as defined-sets, aliasing, and payload-based filtering 
> expands the attack surface, warranting additional mitigation recommendations.

The document does cover defined-sets in the Security Considerations section of 
the document. Maybe some sentences could be added for aliasing and 
payload-based filtering.

>  
> While RFC 8341 provides a foundation for user and data access control, it 
> does not explicitly address ACL-specific threats such as unauthorized 
> modifications or tampering. Given the critical role ACLs play in security 
> policy enforcement, it may be beneficial to reinforce best practices tailored 
> to ACL configurations, such as:
>  
> Requiring digital signatures (e.g., PKI-based certificates, HMAC) for ACL 
> modifications to ensure authenticity.
> Deploying anomaly detection mechanisms to detect and alert on unusual ACL 
> modifications.
> Restricting ACL modifications to predefined maintenance windows to reduce 
> exposure to accidental or unauthorized changes.

All good points. However, I believe they are not specific to ACL configuration. 
NETCONF/RESTCONF already requires secure authenticated sessions to be 
established to make any modifications or read the config. Repeating your first 
bullet item will be redundant in this document.

>  
> It doesn't look like that there is any BCP specifically addressing ACL 
> integrity protections, perhaps referencing broader security best practices 
> from RFC 2196 (Site Security Handbook) or RFC 4949 (Internet Security 
> Glossary) could be helpful.

The last two bullet items are items that should be targeted for a BCP like RFC 
2196.

Cheers.

>  <> 
> Linda
>  
> -----Original Message-----
> From: [email protected] <mailto:[email protected]> 
> <[email protected] <mailto:[email protected]>> 
> Sent: Wednesday, January 29, 2025 12:52 AM
> To: Linda Dunbar <[email protected] 
> <mailto:[email protected]>>; [email protected] <mailto:[email protected]>
> Cc: [email protected] 
> <mailto:[email protected]>; [email protected] 
> <mailto:[email protected]>; [email protected] <mailto:[email protected]>
> Subject: RE: Secdir last call review of draft-ietf-netmod-acl-extensions-13
>  
> Hi Linda, 
>  
> Thank you for the review. 
>  
> You are completely right about the risks, which are not specific to this I-D 
> but are similar to RFC8519. This is why we do have the following:
>  
>       Similar to [RFC8519], unauthorized write access to these list can
>       allow intruders to modify the entries so as to permit traffic that
>       should not be permitted, or deny traffic that should be permitted.
>       The former may result in a DoS attack, or compromise a device.
>       The latter may result in a DoS attack. 
>  
> For sure, unauthorized access to configuration data (not only ACLs) will 
> cause a lot of damage. Consider access to a routing configuration, address 
> allocation, etc. So, if there are any robust measures to recommend, these 
> should be applicable beyond ACL case. This is why we leverage common blocks 
> such as RFC8341 for control of users/data access, mutual authentication, etc. 
>  
> I think that the guards in the spec are good ones. However, if you are aware 
> of an ** authoritative BCP ** that we can consider, please let us know.
>  
> Thank you.
>  
> Cheers,
> Med
>  
> > -----Message d'origine-----
> > De : Linda Dunbar via Datatracker <[email protected] 
> > <mailto:[email protected]>> Envoyé : mardi 28 
> > janvier 2025 19:23 À : [email protected] <mailto:[email protected]> Cc : 
> > [email protected] 
> > <mailto:[email protected]>; last- [email protected] 
> > <mailto:[email protected]>; 
> > [email protected] <mailto:[email protected]> Objet : Secdir last call review of 
> > draft-ietf-netmod-acl-
> > extensions-13
> > 
> > Reviewer: Linda Dunbar
> > Review result: Not Ready
> > 
> > I have reviewed this document as part of the SEC area directorate's 
> > ongoing effort to review all IETF documents being processed by the 
> > IESG.  These comments were written primarily for the benefit of the 
> > Security area directors.
> > Document editors and WG chairs should treat these comments just like 
> > any other last-call comments.
> > 
> > Summary: The document defines extensions to the ACLs YANG Model 
> > specified in RFC 8519. While the description is clear, it lacks 
> > details on the mitigation methods for ACL Manipulation Risks.
> > 
> > New features such as defined-sets, aliasing, and payload-based 
> > filtering introduce potential security risks if not properly 
> > authenticated and authorized.  An attacker could: a) Modify ACL 
> > entries to bypass security policies (e.g., allow the malicious 
> > traffic); b) Introduce denial-of-service
> > (DoS) conditions by blocking legitimate traffic.
> > 
> > To mitigate these risks, the document should include recommendations 
> > for security best practices, such as,  requiring the ACL configuration 
> > changes to be digitally signed using PKI- based certificates or HMAC 
> > (Hash-based Message Authentication Code); maintaining a detailed log 
> > of ACL modifications; storing a hash of ACL configurations in a 
> > tamper-resistant database; implementing anomaly detection mechanisms 
> > to trigger alerts for unusual ACL modification; restricting ACL 
> > modifications only during maintenance windows to minimize accidental 
> > or unauthorized changes,  etc.
> > 
> > Adding these security controls would significantly enhance the 
> > document's robustness against ACL manipulation attacks.
> > 
> > Best Regards, Linda Dunbar
> > 
> > 
>  
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Mahesh Jethanandani
[email protected]






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