TC:Medium:Collaborative Research:Techniques to Retrofit Legacy Code with Security

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。虽然可能是不幸的，但作为一个实际问题，软件通常以功能为主要目标构建，而安全特性只是在以后添加，通常是在识别漏洞之后。为了在安全改造过程中降低成本并增加保证，我们的目标是开发一种涉及自动化和半自动化工具和技术的方法，以向遗留软件系统添加授权策略实施功能。主要的见解是，涉及改进代码的任务的主要部分可以或已经被自动化了，因此设计过程的重点是支持进一步的自动化，并将这些任务聚合到一个单一的、一致的方法中。更具体地说，正在开发的技术和工具是：(1)通过分析和检测带注释的应用程序源代码来识别和标记与安全相关的对象和I/O通道；(2)插入代码以调解对标记实体的访问；(3)将插入的检查抽象为与策略相关的、安全敏感的操作，这些操作由应用程序的安全策略授权（或拒绝）；(4)在部署时将改进后的遗留代码与站点的特定策略集成，以确保通过高级策略分析，应用程序正确地执行站点的策略；(5)验证改进后的应用程序正确地执行OS策略委托。正在开发的技术和工具不仅对改进有用，而且对增加和验证已经配备了安全功能的现有代码也很有用；因此，在创造更安全的软件方面，要提高最先进的技术。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Though perhaps unfortunate, as a practical matter software is oftenbuilt with functionality as a primary goal, and security features areonly added later, often after vulnerabilities have been identified.To reduce the cost and increase assurance in the process of securityretrofitting, the aim to develop a methodology involving automated andsemi-automated tools and techniques to add authorization policyenforcement functionality to legacy software systems.The main insight is that major portions of the tasks involved inretrofitting code can be or already have been automated, so the designprocess focuses on enabling further automation and aggregating thesetasks into a single, coherent approach.More specifically, techniques and tools are being developed to: (1)identify and label security-relevant objects and I/O channels byanalyzing and instrumenting annotated application source code; (2)insert code to mediate access to labeled entities; (3) abstract theinserted checks into policy-relevant, security-sensitive operationsthat are authorized (or denied) by the application's security policy;(4) integrate the retrofitted legacy code with the site's specificpolicy at deployment time to ensure, through advanced policy analysis,that the application enforces that site's policy correctly, and (5)verify correct enforcement of OS policy delegation by the retrofittedapplication.The techniques and tools being developed are useful not onlyfor retrofitting, but also for augmenting and verifying existing codealready outfitted with security functionality; hence improving thestate-of-the-art in creating more secure software.