Cloud Data Security: Use (Rough Cut)By Rich
In our last post in this series, we covered the cloud implications of the Store phase of Data Security Cycle (our first post was on the Create phase). In this post we’ll move on to the Use phase. Please remember we are only covering technologies at a high level in this series – we will run a second series on detailed technical implementations of data security in the cloud a little later.
Use includes the controls that apply when the user is interacting with the data – either via a cloud-based application, or the endpoint accessing the cloud service (e.g., a client/cloud application, direct storage interaction, and so on). Although we primarily focus on cloud-specific controls, we also cover local data security controls that protect cloud data once it moves back into the enterprise. These are controls for the point of use – we will cover additional network based controls in the next phase.
Users interact with cloud data in three ways:
- Web-based applications, such as most SaaS applications.
- Client applications, such as local backup tools that store data in the cloud.
- Direct/abstracted access, such as a local folder synchronized with cloud storage (e.g., Dropbox), or VPN access to a cloud-based server.
Cloud data may also be accessed by other back-end servers and applications, but the usage model is essentially the same (web, dedicated application, direct access, or an abstracted service).
Steps and Controls
|Activity Monitoring and Enforcement||Database Activity Monitoring|
Application Activity Monitoring
|Endpoint Activity Monitoring|
File Activity Monitoring
Portable Device Control
|Rights Management||Label Security||Enterprise DRM|
|Logical Controls||Application Logic|
Row Level Security
|Application Security||see Application Security Domain section|
Activity Monitoring and Enforcement
Activity Monitoring and Enforcement includes advanced techniques for capturing all data access and usage activity in real or near-real time, often with preventative capabilities to stop policy violations. Although activity monitoring controls may use log files, they typically include their own collection methods or agents for deeper activity details and more rapid monitoring. Activity monitoring tools also include policy-based alerting and blocking/enforcement that log management tools lack.
None of the controls in this category are cloud specific, but we have attempted to show how they can be adapted to the cloud. These first controls integrate directly with the cloud infrastructure:
- Database Activity Monitoring (DAM): Monitoring all database activity, including all SQL activity. Can be performed through network sniffing of database traffic, agents installed on the server, or external monitoring, typically of transaction logs. Many tools combine monitoring techniques, and network-only monitoring is generally not recommended. DAM tools are managed externally to the database to provide separation of duties from database administrators (DBAs). All DBA activity can be monitored without interfering with their ability to perform job functions. Tools can alert on policy violations, and some tools can block certain activity. Current DAM tools are not cloud specific, and thus are only compatible with environments where the tool can either sniff all network database access (possible in some IaaS deployments, or if provided by the cloud service), or where a compatible monitoring agent can be installed in the database instance.
- Application Activity Monitoring: Similar to Database Activity Monitoring, but at the application level. As with DAM, tools can use network monitoring or local agents, and can alert and sometimes block on policy violations. Web Application Firewalls are commonly used for monitoring web application activity, but cloud deployment options are limited. Some SaaS or PaaS providers may offer real time activity monitoring, but log files or dashboards are more common. If you have direct access to your cloud-based logs, you can use a near real-time log analysis tool and build your own alerting policies.
- File Activity Monitoring: Monitoring access and use of files in enterprise storage. Although there are no cloud specific tools available, these tools may be deployable for cloud storage that uses (or presents an abstracted version of) standard file access protocols. Gives an enterprise the ability to audit all file access and generate reports (which may sometimes aid compliance reporting). Capable of independently monitoring even administrator access and can alert on policy violations.
The next three tools are endpoint data security tools that are not cloud specific, but may still be useful in organizations that manage endpoints:
- Endpoint Activity Monitoring: Primarily a traditional data security tool, although it can be used to track user interactions with cloud services. Watching all user activity on a workstation or server. Includes monitoring of application activity; network activity; storage/file system activity; and system interactions such as cut and paste, mouse clicks, application launches, etc. Provides deeper monitoring than endpoint DLP/CMF tools that focus only on content that matches policies. Capable of blocking activities such as pasting content from a cloud storage repository into an instant message. Extremely useful for auditing administrator activity on servers, assuming you can install the agent. An example of cloud usage would be deploying activity monitoring agents on all endpoints in a customer call center that accesses a SaaS for user support.
- Portable Device Control: Another traditional data security tool with limited cloud applicability, used to restrict access of, or file transfers to, portable storage such as USB drives and DVD burners. For cloud security purposes, we only include tools that either track and enforce policies based on data originating from a cloud application or storage, or are capable of enforcing policies based on data labels provided by that cloud storage or application. Portable device control is also capable of allowing access but auditing file transfers and sending that information to a central management server. Some tools integrate with encryption to provide dynamic encryption of content passed to portable storage. Will eventually be integrated into endpoint DLP/CMF tools that can make more granular decisions based on the content, rather than blanket policies that apply to all data. Some DLP/CMF tools already include this capability.
- Endpoint DLP: Endpoint Data Loss Prevention/Content Monitoring and Filtering tools that monitor and restrict usage of data through content analysis and centrally administered policies. While current capabilities vary highly among products, tools should be able to monitor what content is being accessed by an endpoint, any file storage or network transmission of that content, and any transfer of that content between applications (cut/paste). For performance reasons endpoint DLP is currently limited to a subset of enforcement policies (compared to gateway products) and endpoint-only products should be used in conjunction with network protection in most cases (which we will discuss in the next phase of the lifecycle).
At this time, most activity monitoring and enforcement needs to be built into the cloud infrastructure to provide value. We often see some degree of application activity monitoring built into SaaS offerings, with some logging available for cloud databases and file storage. The exception is IaaS, where you may have full control to deploy any security tool you like, but will need to account for the additional complexities of deploying in virtual environments which impact the ability to route and monitor network traffic.
We covered the rights management options in the Create and Store sections. They are also a factor in the this phase (Use), since this is another point where they can be actively enforced during user interaction
In the Store phase rights are applied as data enters storage, and access limitations are enforced. In the Use phase, additional rights are controlled, such as data modification, export, or more-complex usage patterns (like printing or copying).
Logical controls expand the brute-force restrictions of access controls or EDRM that are based completely on who you are and what you are accessing. Logical controls are implemented in applications and databases and add business logic and context to data usage and protection. Most data-security logic controls for cloud deployments are implemented in application logic (there are plenty of other logical controls available for other aspects of cloud computing, but we are focusing on data security).
- Application Logic: Enforcing security logic in the application through design, programming, or external enforcement. Logical controls are one of the best options for protecting data in any kind of cloud-based application.
- Object (Row) Level Security: Creating a ruleset restricting use of a database object based on multiple criteria. For example, limiting a sales executive to only updating account information for accounts assigned to his territory. Essentially, these are logical controls implemented at the database layer, as opposed to the application layer. Object level security is a feature of the Database Management System and may or may not be available in cloud deployments (it’s available in some standard DBMSs, but is not currently a feature of any cloud-specific database system).
- Structural Controls: Using database design features to enforce security. For example, using the database schema to limit integrity attacks or restricting connection pooling to improve auditability. You can implement some level of structural controls in any database with a management system, but more advanced structural options may only be available in robust relational databases. Tools like SimpleDB are quite limited compared to a full hosted DBMS. Structural controls are more widely available than object level security, and since they don’t rely on IP addresses or external monitoring they are a good option for most cloud deployments. They are particularly effective when designed in conjunction with application logic controls.
Aside from raw storage or plain hosted database access, most cloud deployments involve enterprise applications. Effective application security is thus absolutely critical to protect data, and often far more important than any access controls or other protections. A full discussion of cloud application security issues is beyond the scope of this post, and we recommend you read the Cloud Security Alliance Guidance for more details.
Cloud SPI Tier Implications
Software as a Service (SaaS)
Most usage controls in SaaS deployments are enforced in the application layer, and depend on what’s available from your cloud provider. The provider may also enforce additional usage controls on their internal users, and we recommend you ask for documentation if it’s available. In particular, determine what kinds of activity monitoring they perform for internal users vs. cloud-based users, and if those logs are ever available (such as during the investigation of security incidents). We also often see label security in SaaS deployments.
Platform as a Service (PaaS)
Depending on your PaaS deployment, it’s likely that application logic will be your best security option, followed by activity monitoring. If your PaaS provider doesn’t provide the level of auditing you would like, you may be able to capture activity within your application before it makes a call to the platform, although this won’t capture any potential direct calls to the PaaS that are outside your application.
Infrastructure as a Service (IaaS)
Although IaaS technically offers the most flexibility for deploying your own security controls, the design of the IaaS may inhibit deployment of many security controls. For example, monitoring tools that rely on network access or sniffing may not be deployable. On the other hand, your IaaS provider may include security controls as part of the service, especially some degree of logging and/or monitoring.
Database control availability will depend more on the nature of the infrastructure – as we’ve mentioned, full hosted databases in the cloud can enforce many, if not all, of the traditional database security controls.
Endpoint-based usage controls are enforceable in managed environments, but are only useful in private cloud deployments where access to the cloud can be restricted to only managed endpoints.