如今,web浏览器安装在几乎所有的电脑和移动设备。因为他们的声望、特权和功能,web浏览器已经成为一个有吸引力的攻击者的目标。虽然相对较难找到一个漏洞在浏览器代码中,浏览器扩展和web应用程序提供充足的安全漏洞和攻击者的新机会。在本文中,我们认为浏览器扩展和web应用程序有一个丰富的供应easy-to-exploit漏洞但可以减少攻击表面和保护用户从大量的web浏览器浏览器内通过实现防御攻击。支持这种说法,我们开发了新方法自动检测浏览器扩展代码重用的弱点,提出了一个浏览器防御保护网络用户免受恶意或脆弱的扩展和引入新方法在野外测量反映使用XSS技术和评估现有的浏览器内置过滤器的有效性。在第一部分,我们首先要确定一个extension-reuse漏洞,允许对手重用安全敏感的功能从无害的合法的扩展。然后我们交叉射击,一个轻量级静态分析器遗留Firefox扩展的自动发现实例extension-reuse漏洞,产生业绩,证实存在的漏洞,和输出利用模板来帮助用户快速构建概念验证工具的利用。在第二部分中,我们探讨一些似是而非的使用恶意的攻击或利用一个脆弱的扩展延伸。然后,我们介绍一个新的浏览器防御是一个运行时政策执行者提供细粒度控制用户在浏览器扩展的行为。我们表明,我们提出的辩护可以有效防止混凝土,现实世界的Firefox扩展攻击没有不利影响用户的浏览体验。 In the third part, we conduct a longitudinal study of 134K reflected Cross-Site Scripting exploits submitted by independent security researchers spanning a period of nearly ten years. In order to detect the exploitation techniques used, we combine the static and dynamic techniques and execute the attacks in a sandbox environment. Our results suggests that the web applications still has an abundant supply of easy-to-exploit vulnerabilities and implementing defenses inside the browser is effective against the most prevalent type of attacks and a promising avenue for further enhancements.展开/折叠切换
低级编程语言中的内存损坏计算机系统继续造成重大威胁。腐败的主要原因,因此,攻击是没有记忆和类型安全不安全的编程语言,如C / c++。设计一个低成本、全面记忆腐败缓解策略从来都不是一件容易的事。虽然缓解技术取得了重大进展,现有对策不足由于有限覆盖或高性能开销。轻量级防御较弱的政策并导致较低的性能开销。然而,这些防御机制必须为了有一个更好的理解它们的局限性。另一条线的研究侧重于记忆的缓解类的腐败,如时间或空间记忆腐败。时间记忆有害的腐败似乎小于空间腐败。然而,他们正在越来越多地利用在野外。最先进的解决方案来缓解时间内存损坏要求空间记忆安全来保护他们的内存中的元数据。这个需求凸显出两个这些技术的局限性。 First, without external protection, they themselves are not robust against attacks or evasions. Second, requiring spatial safety can significantly increase the already high runtime overhead. Furthermore, many of the existing mitigations store a considerable amount of metadata in memory, increasing the memory footprint by as much as 2 times. Recently, hardware-assisted approaches have gained attention for reducing the performance overhead and providing more comprehensive protection. ARM Memory Tagging Extension (MTE) and SPARC Application Data Integrity (ADI) are notable examples that aim to detect and mitigate memory corruption attacks in development and deployment stages. They detect both spatial and temporal memory corruption probabilistically. However, the efficiency of these protections directly depends on the design of memory allocators, which so far has not been systematically studied.In this thesis, I present novel research into understanding and mitigating memory corruption attacks by exploring current solutions and designing a new system. First, I provide a comprehensive study on the security and practicality of Runtime Type Checking (RTC)-based CFI. Then, I present a robust points-to authentication, a novel runtime scheme for detecting temporal memory corruptions in the heap section. I built a prototype system, called PTAuth, that realizes this scheme on ARM architectures. Finally, I perform a security analysis of tag assigning strategies in memory tagging approaches. I analyze existing implementations of tag assigning strategies and enumerate important design limitations of each one across different memory allocators.--Author's abstract展开/折叠切换
由于web浏览器提供的广泛的特点,现代网站包括各种类型的内容,如JavaScript和层叠样式表(CSS)来创建交互式用户界面。浏览器厂商也提供了扩展与附加的有用功能,加强web浏览器默认不一定是维护或支持。然而,包括内容可以引入安全风险这些网站的用户,不知道这两个网站运营商和用户。此外,浏览器的解释资源的URL可能非常不同于web服务器解析URL如何确定哪些资源应该返回到浏览器。URL可能不对应于一个实际的服务器端文件系统结构,内部或web服务器可能重写URL的组成部分。这个语义web浏览器和web服务器之间的脱节在解释相对路径(路径混淆)可以利用相对路径覆盖(RPO)。另一方面,即使艰难扩展为web浏览器提供有用的附加功能,他们也日益流行的攻击向量。由于高度的特权扩展,扩展曾被虐待注入广告网页把收入从内容出版商和潜在暴露用户的恶意软件。在这个论文中,我提出新颖的研究理解和减轻安全风险的内容包含在web浏览器保护网站出版商以及他们的用户。首先,我将介绍一个浏览器的方法称为切除自动检测并阻止恶意第三方内容夹杂物作为web页面被加载到执行期间用户的浏览器或浏览器扩展。 Then, I propose OriginTracer, an in-browser approach to highlight extension-based content modification of web pages. Finally, I present the first in-depth study of style injection vulnerability using RPO and discuss potential countermeasures.展开/折叠切换
最初的加州和ncv数据集之间的差异随着时间的推移,减少和两个数据集是认为聚集的犯罪类别。所使用的不同定义和方法研究测试和解释了两个数据集之间的融合,这些研究经常报道不同的结果。本研究的两个目标包括理解和解释两个数据集之间的融合。研究数据来自多个来源。多个分析策略是用来测试收敛,和自回归模型与有关预测变量估计解释收敛。支持图形和相关性分析所有类别的两个系列之间的融合。然而,协整检验表明,该系列共合体的入室盗窃,抢劫和暴力犯罪的收敛过程。两个数据集之间的差异率一直很受向警方报告犯罪的百分比。因此,收敛性测试是重复调整后的加州率报告,但结果没有显著差异。自回归模型的结果表明,增加数量的警察和方法论的变化在1992年的中译是重要因素,减少了加州和ncv数据集之间的差异。 The determining convergence largely depends on the definition of convergence. In this case, a perfect convergence, in which the two series overlap and move together, is neither possible nor desirable because the UCR and NCVS use nonidentical measurements to measure nonidentical sets of crimes. The study provides important research, policy, and methodological implications and suggests future research directions on the subject.展开/折叠切换
本论文旨在进一步了解polymer-ceramic复合材料的界面相互作用,识别方法提高相间,并创建高性能复合材料。在这里,我们报告三个不同polymer-ceramic系统重点改善最终复合材料的力学和热性能。第一个系统侧重于提高hydrogel-based复合材料的强度使用磁微尺度陶瓷增援部队保持一致。我们已经表明,alginate-hydroxyapatite相间成功转移压力从水凝胶micro-ceramic强化引入一类新的承载组织支架。此外,水凝胶的力学性能可裁制成衣的根据填料取向通过使用磁处理技术。最后,我们表明,水凝胶与垂直对齐展览高延性,暗示一个令人兴奋的新纤维增强复合材料的增韧机制。在第二个系统、半晶状的聚合物基质与陶瓷氧化铝micro-platelets钢筋。matrix-filler界面直接提高了本地结晶聚合物矩阵使用nanofiller成核剂,创建一个层次结构刚度矩阵和聚合物之间的梯度。在这项工作中,我们使用聚丙烯、氧化铝、和碳纳米管,但是这个系统的基本原理可以应用于各种不同的材料组合。我们已经成功地显示一个新颖的方法来定制相间氧化铝与聚丙烯之间利用纳米颗粒吸附和当地聚合物结晶技术可用于创建一个层次结构刚度梯度。 This chapter also shows that the crystal nucleation and growth mechanisms match that of polypropylene-CNT filled systems, even when the CNT is adsorbed to the flat alumina surface. Finally, the locally crystallized polymer will likely improve the thermal heat transfer by introducing higher density polymer region immediately surrounding the filler. In the third system, the thermal conductivity of thermoset composites reinforced with ceramic filler is discussed. Thermal conductivity of polymeric materials is inherently low, therefore introducing high thermal conductivity ceramic filler improves the overall thermal properties. Here we discuss the most important aspects to creating these composites, including filler alignment, geometry, and introducing thermal pathways by creating a percolated network with the ceramic filler. A novel method to drive percolation in single layer, hBN-epoxy composites via Marangoni induced assembly is shown. Thermal spreading test results show this method of aligning and percolating the hBN platelets significantly increases the thermal heat transfer through the interphase. Finally, this chapter shows an application-based example of how thermal heat spreaders can be used in place of traditional metal heat management solutions. This thesis first discusses the importance of tailoring interphases in discontinuous composite materials. Following a detailed discussion on composite materials, we then introduce each individual system, review the current state of our research and key results, and discuss proposed methods to further improve the interfacial interactions and show property improvements in the final composite system.--Author's abstract展开/折叠切换