Today, many tools exist that attempt to find possible vulnerabilities in Android applications, e.g., FlowDroid, Fortify, or AppScan. However, all these tools aim to detect vulnerabilities or (sometimes) tainted flows and present the reviewer detected possible issues of an analyzed Android application. None of these tools supports the identification of implemented security features in code, although this aspect is also relevant to developers as well as reviewers. To address this open problem, we present a program comprehension approach based on connected object process graphs (COPGs) containing interacting objects described by security patterns in this paper. The feasibility of our approach is evaluated qualitatively with 25 security-critical Android applications from Google Play with almost 7 million lines of code. We currently support 17 security pattern variants with about 199 correctly detected pattern instances in the apps. We also define a benchmark of non-trivial, security-critical Android apps, which can also be used for other security analysis tasks based on the static analysis framework Soot. With this benchmark, our analysis yields a precision of 99% and a recall of 80%. Finally, we discussed our approach and the developed tool with six software security experts from the SAFECode organization to obtain additional feedback.

Since Gamma et al. published their design patterns, patterns are very popular in the area of software engineering. They provide best practice to handle recurring problems during the software development phase. Three years later, security patterns appeared and provided solutions for security problems. Besides the name analogy, design and security patterns should be very similar except for the security factor. In research and industry software engineering with design patterns is widespread. However, some researchers suspect that security-pattern engineering is made difficult by some issues such as terminology or description form. Detecting adoption problems can help to improve security patterns in future. Thus, they can promote the awareness of security especially in the software maintenance phase where many programmers first give attention to security problems. Therefore, we will compare design and security patterns to find indicators for negative impact on security pattern engineering in software development. We address this issue on inspecting the aspects classification, description form, provided code examples, and usage in the software life-cycle. We determine the degree of maturity of software-security patterns by comparing them to the well-explored design patterns. To achieve the objective, we inspect the pattern terminology and conducted a study on the used description forms including provided UML diagrams and code examples. Moreover, a literature review is conducted to compare their state of research w.r.t. the software life-cycle. The maturity degree of security patterns compared to common design patterns differs and we depict further research opportunities on security patterns.

Security patterns describe best practices to handle recurring security problems. Patterns are presented with a special description form that depicts the pattern's specific properties. A description form consists of different sections such as Motivation, Problem or Solution. Many security patterns exist and their description forms are very different. This heterogeneity is a problem for comparing security patterns, their comprehension and application in the software design, and usage in tools that should support their selection in the software development process. Some researchers desire a unique description form and others suggest description forms with new sections that capture security-specific aspects. In order to assess whether additional security-specific facets are actually needed, we assess existing descriptions of software-security patterns in depth. We compare the sections of software-security patterns publications to the common GoF and POSA design pattern templates to identify additionally used sections. Moreover, we align these additionally used sections of software-security patterns to the sections of the aforementioned description forms. Finally, we scan the additional sections to identify sections that possibly capture security-specific properties.

Mobile phones have developed into complex platforms with large numbers of installed applications and a wide range of sensitive data. Application security policies limit the permissions of each installed application. As applications may interact, restricting single applications may create a false sense of security for end users, while data may still leave the mobile phone through other applications. Instead, the information flow needs to be policed for the composite system of applications in a transparent manner. In this paper, we propose to employ static analysis, based on the software architecture and focused on data-flow analysis, to detect information flows between components. Specifically, we aim to reveal transitivity-of-trust problems in multi-component mobile platforms. We demonstrate the feasibility of our approach with two Android applications.

Software security is an emerging area in software development. More and more vulnerabilities are published and highlight the endangerment of systems. Hence, software designers and programmers are increasingly faced with the need to apply security solutions to software systems. Security patterns are best practices to handle recurring security problems. The abundance of documented security patterns calls for meaningful classifications to ease searching and assessing the right pattern for a security problem at hand. Existing classifications for security patterns consider only a small number of patterns and their purpose is often focused on implementation issues. Therefore, we identify missing aspects in existing classifications and the similarities between design and security pattern classifications. Based on that, we introduce two new classification schemes. The first is based on application domains formed by a literature survey on security patterns published in the period of 1997 to mid-2012 to cover the whole bandwidth of existing security patterns. The second is based on a subset of the collected patterns that are concerned with software and combines pattern-recognition needs and security aspects. Keywords-Security Patterns, Design Patterns.

Mobile phones have developed into complex platforms with large numbers of installed applications and a wide range of sensitive data. Application security policies limit the permissions of each installed application. As applications may interact, restricting single applications may create a false sense of security for the end users while data may still leave the mobile phone through other applications. Instead, the information flow needs to be policed for the composite system of applications in a transparent and usable manner. In this paper, we propose to employ static analysis based on the software architecture and focused data flow analysis to scalably detect information flows between components. Specifically, we aim to reveal transitivity of trust problems in multi-component mobile platforms. We demonstrate the feasibility of our approach with Android applications, although the generalization of the analysis to similar composition-based architectures, such as Service-oriented Architecture, can also be explored in the future.

Software security is becoming more and more important with the increasing number of applications and platforms connected to the Internet, for example, enterprise applications, smartphones or the iPad. The growing importance makes it a progressively interesting field for developers, software designers, end users, and enterprises. Fixing security bugs belongs to the traditional field of software maintainace what makes it also necessary to apply software-comprehension techniques. In the following we present our ongoing research on software-security comprehension, a first step towards program comprehension tailored to the needs of security experts.

Software security has made great progress, code analysis tools are widely-used in industry for detecting common implementation-level security bugs. However, given the fact that we must deal with legacy code we plead to employ the techniques long been developed in the research area of program comprehension for software security. In cooperation with a security expert, we carried out a case study with the mobile phone platform Android, and employed the reverse engineering tool-suite Bauhaus for this security assessment. During the investigation we found some inconsistencies in the implementation of the Android security concepts. Based on the lessons learned from the case study, we propose several research topics in the area of reverse engineering that would support a security analyst during security assessments.

Today, software security is an issue with increasing importance. Developers, software designers, end users, and enterprises have their own needs w.r.t. software security. Therefore, when designing software, security should be built in from the beginning, for example, by using security patterns. Utilizing security patterns already improves the security of software in early software development stages. In this paper, we show how to detect security patterns in code with the help of a reverse engineering tool-suite Bauhaus. Specifically, we describe an approach to detect the Single Access Point security pattern in two case studies using the hierarchical reflexion method implemented in Bauhaus.