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Internet of Things (IoT) for smart homes enhances convenience; however, it also introduces the risk of the leakage of private data. TOP10 IoT of OWASP 2018 shows that the first vulnerability is ”Weak, easy to predict, or embedded passwords.” This problem poses a risk because a user can not fix, change, or detect a password if it is embedded in firmware because only the developer of the firmware can control an update. In this study, we propose a lightweight method to detect the hardcoded username and password in IoT devices using a static analysis called Socket Search and String Search to protect from first vulnerability from 2018 OWASP TOP 10 for the IoT device. The hardcoded login information can be obtained by comparing the user input with strcmp or strncmp. Previous studies analyzed the symbols of strcmp or strncmp to detect the hardcoded login information. However, those studies required a lot of time because of the usage of complicated algorithms such as symbolic execution. To develop a lightweight algorithm, we focus on a network function, such as the socket symbol in firmware, because the IoT device is compromised when it is invaded by someone via the Internet. We propose two methods to detect the hardcoded login information: string search and socket search. In string search, the algorithm finds a function that uses the strcmp or strncmp symbol. In socket search, the algorithm finds a function that is referenced by the socket symbol. In this experiment, we measured the ability of our proposed method by searching six firmware in the real world that has a backdoor. We ran three methods: string search, socket search, and whole search to compare the two methods. As a result, all methods found login information from five of six firmware and one unexpected password. Our method reduces the analysis time. The whole search generally takes 38 mins to complete, but our methods finish the search in 4-6 min.

This study explores novice programmers' abilities to design and code a string manipulation task in C after one semester of tertiary instruction. String manipulation is an important skill for novice programmers to master as most applications deal with text and/or interact with the user. The analysis shows most novice programmers (88%) were able to sketch their own programming plan to print a word in pyramid style. 53% of students chose to control the printing letter by letter (character level) and 32% updated and printed the word as a whole (string level). However only 6% used string functions, apart from strlen() and strcmp(), to implement their plan. This indicated a low level of transfer from their most recent class activity which focused on the C string library. As expected, not all succeeded to correctly implement their plan: 56% were correct at character level and 63% at string level, resulting in 49% of the whole cohort completing the task. Their code has been thoroughly analysed to identify implementation issues, and logical, syntax and plan errors are reported and discussed.

We introduce a robust semantics-driven technique for program equivalence checking. Given two functions we find a trace alignment over a set of concrete executions of both programs and construct a product program particularly amenable to checking equivalence. We demonstrate that our algorithm is applicable to challenging equivalence problems beyond the scope of existing techniques. For example, we verify the correctness of the hand-optimized vector implementation of strlen that ships as part of the GNU C Library, as well as the correctness of vectorization optimizations for 56 benchmarks derived from the Test Suite for Vectorizing Compilers.

International audience; We present a modular analysis able to tackle out-of-bounds accesses in C strings. This analyzer is modular in the sense that it infers and tabulates (for reuse) input/output relations, automatically partitioned according to the shape of the input state. We show how the inter-procedural iterator discovers and generalizes contracts in order to improve their reusability for further analysis. This analyzer was implemented and was able to successfully analyze and infer relational contracts for functions such as strcpy, strcat.

A case study is presented that empirically analyzes the use of known unsafe functions in gcc, a well-known general purpose software system, along with their distribution over a 5-year period from, 2012 through 2016. The 5-year history of gcc studied is comprised of a total of over 26 million lines of code. gcc was statically analyzed with the use of srcML and a tool created by one of the authors. A count of each unsafe function type present in each year of the system was recorded, along with a count of safe replacement functions, and their distributions analyzed. The results were compared to findings from a previous study on networking and mobile systems. The results show free, strcmp, strlen, and memcpy to be the most prevalent unsafe functions used among the years of gcc studied. This information can help developers by showing where they should direct their attention when refactoring their system to improve security, and thereby improve the system's robustness, reliability, and overall quality. By focusing on the most prevalent unsafe functions, developers can plan their refactoring process to be more effective. The fact that unsafe functions are still being used despite there being safer alternatives shows a need for new security standards, better education about security and security issues, and supervision of programmers to ensure they follow those standards.

C++ template metaprogramming is an emerging direction of generative programming: with proper template definitions we can enforce the C++ compiler to execute algorithms at compilation time. Template metaprograms have become essential part of today's C++ programs of industrial size; they provide code adoptions, various optimizations, DSL embedding, etc. Besides the compilation time algorithms, template metaprogram data-structures are particularly important. From simple typelists to more advanced STL-like data types there are a variety of such constructs. Interesting enough, until recently string, as one of the most widely used data type of programming, has not been supported. Although, boost::mpl::string is an advance in this area, it still lacks the most fundamental string operations. In this paper, we analysed the possibilities of handling string objects at compilation time with a metastring library. We created a C++ template metaprogram library that provides the common string operations, like creating sub-strings, concatenation, replace, and similar. To provide real-life use-cases we implemented two applications on top of our Metastring library. One use case utilizes compilation time inspection of input in the domain of pattern matching algorithms, thus we are able to select the more optimal search method at compilation time. The other use-case implements safePrint, a type-safe version of printf - a widely investigated problem. We present both the performance improvements and extended functionality we have achieved in the applications of our Metastring library.