Home > Articles > Security > General Security and Privacy

  • Print
  • + Share This
This chapter is from the book

27.4 Discussion

27.4.1 A Positive Experience

Optimizing the separation between application and security logic is an important objective. Our experience with aspect-oriented programming confirms that this technology enables us to achieve this goal. Several smaller case studies made us confident about the potential of this technology, but the actual implementation of the FTP server lifted our confidence. This is not a toy application. Nevertheless, we were able to fully extract security-related code, producing an isolated basic application. This was done despite the fact that the FTP server was not our own code.

AOP has two important advantages for security. Compared to the well-known technique of modularizing the security mechanism, AOP allows us to raise the level of separation by explicitly focusing on the binding between application and security infrastructure. As a result, the average application developer is no longer involved with security (i.e., he no longer has to invoke security mechanisms himself). This job can be left completely to a focused security expert. A second key advantage relates to the security policy rather than to the infrastructure. Using AOP, the overview of the actual security deployment policy (i.e., defining which mechanisms are used and where they are used) is gathered into a few configuration files. Consequently, compared to object-oriented security engineering, a security expert can more easily verify whether a required security policy is valid within a concrete application.

Some practical limitations of the current tools limit the success of our approach. During different case studies, we experienced some technological restrictions with (version 1.1 of) AspectJ, including limitations of the mechanism to select join points, as well as some essential restrictions in the generalization phase toward the framework. To briefly sketch the first problem, a pointcut is conceptually equivalent to a query on an abstract syntax tree representation of the program. The AspectJ tool provides a set of keywords to describe pointcuts. Unfortunately, some queries (e.g., all the classes that override one or more methods of their parent classes) cannot be expressed using this keyword set, which leads to the construction of less elegant workarounds. Regarding the second problem, aspects, and in particular pointcuts, can be made abstract, but they can only be reused in child aspects of the abstract aspect in which they were defined. In our opinion, the primary cause of this restriction is the forced combination of the specification of behavior and composition logic. Since AspectJ aspects are not fully polymorphic, aspect reuse is hard to achieve. We refer to [10, 12, 31] for a more in-depth discussion of these problems. Some of the restrictions we encountered (e.g., the first one) are due to the current implementation of the tool, while others (the second one) are more fundamental issues that are inherent to the basic concepts behind the tool. As AOP is an active research area, this is what one should expect. Case studies, as included in this chapter, should drive the environments to the next stage. Instead of focusing on specifics related to AspectJ, we will focus in the next paragraphs on the requirements for the AOP domain as a whole.

27.4.2 Requirements for AOP Environments

Define the optimal design process. AOP is a new programming paradigm building on established paradigms such as object-oriented programming. Unfortunately, this hinders the average programmer trying to become productive. Conceptually clean and understandable design processes can help alleviate this problem. Obviously, the rapidly changing character of the AOP technology as it is today does not simplify the development of such clean processes. Even with the existence of such processes, the implementation of security aspects still requires detailed knowledge of the security infrastructure. Apart from enabling improved modularization, AOP technology does not help here.

Watch performance. With AOP, the modules of a program are composed into an executable artifact. Many tools currently transform an aspect-based program into a classical (class-based) object-oriented program. This results in extra methods and extra method invocations relative to the equivalent handcrafted program. Moreover, execution of a transformed program often requires extra run-time libraries. Development and language support often involve a trade-off between efficiency and ease of use. Historically, the transition from procedural to object-oriented programming involved the same trade-off. The important issue here is that these languages or tools disable some of the optimization capabilities of the programmer and replace them with a more expressive programming model. While we did not experience unacceptable penalties when testing and deploying the aspect-based FTP server, we stress the relevance of this subject matter in the long run, as technology and tools mature.

For AspectJ in particular, the definition of advice on security-sensitive methods results in the insertion by the AspectJ compiler of one or more extra calls. For instance, a before advice is implemented using a method proxy, which requires extra indirection. Therefore, the generated code is less efficient and introduces more overhead than a direct implementation. Unfortunately, this is the price of generality. Building a less general aspect and a more complex combination tool could improve this situation.

Support testing and debugging. Debugging involves code assessment and correction. In a typical design process, all sorts of tests (black box, white box, stress, and so forth) are used to validate modules. Likewise, when using AOP, the programmer should have the ability to test aspects. This testing must include both the behavior of the aspect, which is part of the security infrastructure, and the binding within different environments (the security policy). Testing aspect behavior is comparable to but different from traditional object testing. Testing the binding is difficult. It must include both information about the deployment environment (type information and possibly context information) and specific application binding information (specific state transferred between different aspects). Today, research on aspect testing is in a very early state, and practical tools are non-existent. Locating erroneous code is complicated by the fact that the running code does not correspond to the written code. Fortunately, current AOP research also focuses on tools that provide a clear visualization of the run-time interaction between aspects and the core application.

Toward trusted code. From a security viewpoint, the explicit separation and consequent composition of security aspects and application objects raise the extra risk of introducing new security holes. In particular, the specific combination mechanisms used in the tool and the tool itself must be part of the trusted computing base, and therefore, they are a primary target for attacks. Let us consider the case of authorization: It should not be possible for a client to directly invoke the end-functionality of a server, circumventing the authorization policy. In this respect, security demands absolute guarantees that the combination process (a.k.a. weaving) cannot be bypassed. At the moment, it is not clear how such guarantees can or will be enforced. This is an important topic for further research.

Specifically, in the context of AspectJ, the output of the actual tool cannot be trusted because the original functionality, without the new aspect code, is simply moved into a new method with a special name. Clever attackers knowing the modus operandi of the tool can exploit the code very easily. As explicitly stated by the tool manual, this problem only arises if not all source code is under the control of the AspectJ compiler. Unfortunately, for practical real-world situations, such as large development processes or dynamic modification of an application, this requirement is often impossible to fulfill.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020