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| === Architecture Diagram === | | === Architecture Diagram === |
| | http://i.imgur.com/L5LC0tj.png |
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| An architecture diagram illustrates how the various components of the service communicate with one another.
| | External services, marked in yellow, communicate to the server which acts as a notification event proxy. |
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| The goal of the architecture diagram is to give the audience a high-level visual representation of how the different components of a system will interact together.
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| An example of this is the diagram below, which is from the old Mozilla F1 service.
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| [https://wiki.mozilla.org/images/thumb/7/78/F1design.png/392px-F1design.png Mozilla F1 Architecture Diagram]
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| The F1 service had multiple components:
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| * a Firefox Add-on that hosted a pane loaded from the Mozilla F1 service that facilitated posting ('sharing') content across multiple services
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| * a back-end that abstracted the 'sharing' process such that a core set of common functions to facilitate easy incorporation of addition services without client updates
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| Rather than providing a detailed assessment of how messages are passed between the various components, this diagram illustrates how the different components interact with one another, but not details about the interactions, or what data is shared between them.
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| The goal of this diagram is to provide a concise overview of the system that provides a frame of reference when someone new to the system is reviewing supporting documentation or code.
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| ==== Key Attributes ====
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| * Clarity; brief descriptions of which components are communicating
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| * Illustrates the boundaries between different services
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| ==== Additional Examples ====
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| * [https://people.mozilla.com/~yboily/identity/assets/images-1/s31.b.jpeg BrowserID Protocol High Level]
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| * [https://people.mozilla.com/~ckoenig/App-Marketplace.jpg Apps MarketPlace] TODO - Replace Me With A Simple Diagram!
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| === Detailed Application Diagram === | | === Detailed Application Diagram === |
| A Detailed Application Diagram is essentially a Data-flow diagram; a data flow diagram enumerates each application or service that is a component of a system, and illustrates each of the paths data can flow through.
| | The SimplePush server has been greatly simplified from the standard protocol in order to meet expected load issues. Where possible, stateful data has been eliminated or factored against (e.g. the normal protocol defines that the client return a list of known ChannelIDs for a given UAID that the server would filter incoming requests against. Since the client discards unknown ChannelIDs, the decision was made that those ChannelIDs would be passed to the client, and left to the client to discard.) |
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| [https://wiki.mozilla.org/images/2/22/BrowserID-Threat-Model.png BrowserID Detailed Diagram]
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| Note that a data-flow diagram is only one example of how this information. The goal is to effectively communicate to the audience how data moves through the system, where different operations are performed, and if detailed enough, how different roles within the system can access different operations.
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| When designing the detailed application diagram it can be useful to assemble a list of each of the subjects in a system.
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| TODO - add references for subject/object/operations in relation to access control models.
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| ==== Key Attributes ====
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| * Clarity; labels for objects are brief, and contain clear references that can be used to cross-reference other documentation
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| * Detailed; ensure that all roles and operations are clearly presented
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| ==== Additional Examples====
| | There is some consideration being made that the data *not* be written to memcache immediately, but only if the client fails to ACK the data as it's being sent (client is offline or fails to ACK data sent by the connected server thread). |
| * [https://wiki.mozilla.org/images/b/bf/MozillaF1-Diagram.png Mozilla F1 Detailed Application Diagram] | |
| * [https://wiki.mozilla.org/images/e/ee/BrowserID-Protocol.png BrowserID Protocol] | |
| * [https://people.mozilla.com/~ckoenig/App-Marketplace.jpg AppStore Threat Model]
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| === Data-flow Enumeration === | | === Data-flow Enumeration === |
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| Data-flow enumeration is an important supplement to the Detailed Application Diagram; it acts as a reference for someone reading the diagram to look up the nature of what information is associated with a call or request between two components.
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| At a minimum, the flow enumeration should be a table indicating an identifier, subject, object, and the operation being performed.
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| In the example below, an excerpt from the [https://wiki.mozilla.org/Security/Reviews/Identity/browserid#1._Provisioning BrowserID provisioning enumeration], the subject, object, and operation are labelled origin, destination, and description, respectively.
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| {| border="1" class="fullwidth-table" | | {| border="1" class="fullwidth-table" |
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| | align="center" style="background:#f0f0f0;"|'''Description''' | | | align="center" style="background:#f0f0f0;"|'''Description''' |
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| |1.A||Relying Party||Implementation Provider|| An interaction with the Relying party invokes the Implementation Provider (IP). | | |1||Client||Server|| Client connects via WebSocket protocol and sends a "hello" JSON packet containing the clients UAID. |
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| |1.B||Implementation Provider||Identity Authority||The IP either has an expired certificate, or no certificate, and directs the client to an Identity Authority landing page for authentication. This authentication process is out of scope of the protocol, and implementation dependent. | | |2||Server||Client|| Server responds with a "hello" JSON response. Server records that the UAID is now active and associates it to the listening websocket connection. |
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| |1.C||Identity Authority||Identity Authority||Code from the IP landing page invokes genKeyPair() to generate a keypair. | | |3a||Server||Client|| Server checks if there is outbound ChannelID updates for UAID and sends them as a "notification" packet" |
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| |1.D||Identity Authority||Implementation Provider||The IP saves the keypair in the client | | |3b||Client||Server|| Client "ack"s the Notification packet. Server deletes any "ack'd" notifications and re-flushes (see step 3a) until no more notifications are present. |
| |}
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| | | |4||Client||Server|| Client registers a new ChannelID and receives a new "endpoint" URL |
| In addition to including the subject, object, operation columns, it can be helpful to include an explicit list of fields which are considered sensitive.
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| | | |4a||Client||App|| (OUT OF BAND) The client relays the Endpoint to the app, which then communicates it back to 3rdPartyServer for later use. |
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| ==== Additional Examples ====
| | |5||3rdPartyServer||Server|| 3rdPartyServer PUTS to "endpoint". The specification requests that the server use "?v=..." however this version information is discarded by the Server. The server records the event to a record in memcache identified by UAID.ChannelID |
| * [https://wiki.mozilla.org/Security/Reviews/Identity/browserid#1._Provisioning BrowserID Data-flow Enumeration]
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| === Threat Analysis ===
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| When performing a security review of an application one of the most important components is a threat analysis. There is a great deal of documentation on how to perform threat analysis, and a number of different techniques that can be used:
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| * [https://www.owasp.org/index.php/Threat_Risk_Modeling OWASP Threat Risk Modelling]
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| * [http://msdn.microsoft.com/en-us/security/aa570413 Microsoft Application Threat Modelling]
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| * [http://csrc.nist.gov/publications/nistpubs/800-30/sp800-30.pdf NIST Risk Management Guide][pdf]
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| For the purposes of a Mozilla Security Review, the means by which someone identifies the threats and risks associated with an application is important, but not specified. If you have questions about how to perform this type of analysis, please contact a member of our team!
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| The resulting threat analysis should be formatted in a clear format, including the following details:
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| * ID - a identifier for the threat
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| * Title - a concise description of the threat
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| * Threat - a description of the threat
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| * Mitigations - a recommendation for a control that can be implemented [1]
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| * Threat Agent - a list of the potential actors considered that would exploit a vulnerability.
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| * Notes - Related comments that contribute to the analysis, but don't belong in other columns
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| * Rating - A qualitative scoring for a vulnerability in the context of this application [2]
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| * Impact - A qualitative score representing the impact should a vulnerability be exploited
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| * Likelihood - A qualitative score representing the likelihood of a vulnerability being exploited. [3]
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| See [https://wiki.mozilla.org/Security/RiskRatings Risk Ratings] for details of how to calculate the qualitative scores.
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| TODO - Glossary Threat, Threat Agent, Vulnerability, Exploit
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| [1] In the case of a threat analysis that contains multiple threats that can be resolved by one or more different controls it may be beneficial to include a separate control table, and list references to controls in that table instead.
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| [2] The rating is calculated by multiplying the impact by the likelihood. This is a naive method, but it's what we have!
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| [3] In the case where different threat agents have different likelihoods, list the likelihoods highest to lowest, in the same order as the threat agents.
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| Below is an excerpt from the [https://wiki.mozilla.org/Security/Reviews/Identity/browserid#Threat_Model BrowserID Threat Analysis]:
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| {| border="1" class="fullwidth-table sortable"
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| | align="center" style="background:#f0f0f0;"|'''ID''' | |
| | align="center" style="background:#f0f0f0;"|'''Title''' | |
| | align="center" style="background:#f0f0f0;"|'''Threat''' | |
| | align="center" style="background:#f0f0f0;"|'''Proposed Mitigations''' | |
| | align="center" style="background:#f0f0f0;"|'''Threat Agent''' | |
| | align="center" style="background:#f0f0f0;"|'''Rating''' | |
| | align="center" style="background:#f0f0f0;"|'''Likelihood''' | |
| | align="center" style="background:#f0f0f0;"|'''Notes''' | |
| | align="center" style="background:#f0f0f0;"|'''Impact''' | |
| | align="center" style="background:#f0f0f0;"|'''Notes'''
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| | 1||SIA may introduce compliance issues||Operating a Secondary Identity Authority may induce compliance requirements with regards to logging user information||Part of the goal of BrowserID is to have Primary Identity Authorities take on this risk as part of their other operations. This can be somewhat mitigated by eliminating support for the webfinger verification process.||Governments, Lawyers||12||3||Governments and other legal actors have the ability to request information from us, either through subpoenas, NSLs, etc. While we hold information that can link user identities to services this information will be a source of risk.||4 – Reputation||Although we are required to comply, and Mozilla would fight such a request to the degree permitted, we would still receive negative press. | | |5a||Server||Client|| IFF the client is actively connected, Server conducts a flush (See step 3*) |
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| | 2||Webfinger Information Leak||Use of the webfinger service for verification discloses each authentication attempt from the Relying Party to the Identity Authority||Implement verification using certificates||Malicious Identity Authority||25||5||This information disclosure is a part of the protocol.||5 – Privacy||This is probably a clear violation of our privacy policies. | | |5b||Server||Magic|| IFF the client is not currently connected, an Proprietary Wake Up method may be employed. The client reconnects and starts at Step 1. |
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| | 3||Chrome Code Injection||Attacker controlled parameters could permit injection of script into browser chrome.||Ensure that any data controlled by the user or relying party is emitted using output encoding.||Malicious Relying Party, Malicious User, Malicious Identity Authority||4||1||Code review and testing should prevent this occuring. The technical complexity of this attack is higher than a vanilla XSS.||4 – User||This gives an attacker the ability to execute code in the context of browser chrome.
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| |} | | |} |
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| | === Threat Analysis === |
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| | A good deal of effort was put forth to reduce the amount of usable data and value of attack for this product. |
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| ==== Additional Examples ====
| | The service is designed to allow remote sites to "wake" an app on a user's device. All actual function happens on the client. If an attacker manages to either identify or use the two UUID4 entries, the most they could do is repeatedly wake an application until the app decides to re-register another ChannelID. An attacker could use this to possibly reduce battery life or increase data costs for a user, but even then, there are much more effective means of doing this. |
| * Mozilla F1 Threats [https://wiki.mozilla.org/Security/Reviews/F1#Threat_Model]
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| * BrowserID Threats [https://wiki.mozilla.org/Security/Reviews/Identity/browserid#Threat_Model]
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| === Security Testing === | | === Security Testing === |
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| The security test plan is a brief explanation of security testing that should be performed, and should include an explanation of what tasks are to be performed, and the approximate amount of time spent performing those tasks. | | The security test plan is a brief explanation of security testing that should be performed, and should include an explanation of what tasks are to be performed, and the approximate amount of time spent performing those tasks. |