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Defensive Programming
Defensive programming is a form of defensive design intended to develop programs that are capable of detecting potential security abnormalities and make predetermined responses. It ensures the continuing function of a piece of software under unforeseen circumstances. Defensive programming practices are often used where high availability, safety, or security is needed. Defensive programming is an approach to improve software and source code, in terms of: * General quality – reducing the number of software bugs and problems. * Making the source code comprehensible – the source code should be readable and understandable so it is approved in a code audit. * Making the software behave in a predictable manner despite unexpected inputs or user actions. Overly defensive programming, however, may safeguard against errors that will never be encountered, thus incurring run-time and maintenance costs. There is also a risk that code traps prevent too many exceptions, potentially resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defensive Design
Defensive design is the practice of planning for contingencies in the design stage of a project or undertaking. Essentially, it is the practice of anticipating all possible ways that an end-user could misuse a device, and designing the device so as to make such misuse impossible, or to minimize the negative consequences. For example, if it is important that a plug is inserted into a socket in a particular orientation, the socket and plug should be designed so that it is physically impossible to insert the plug incorrectly. Power sockets are often keyed in such a manner, to prevent the transposition of live and neutral. They are also recessed in the wall in a way that makes it impossible to touch connectors once they become live. Defensive design in software engineering is called defensive programming. Murphy's law is a well-known statement of the need for defensive design, and also of its ultimate limitations. Applications Computer software Software design entails many way ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rewrite (programming)
A rewrite in computer programming is the act or result of re-implementing a large portion of existing functionality without re-use of its source code. When the rewrite is not using existing code at all, it is common to speak of a rewrite from scratch. Motivations A piece of software is typically rewritten when one or more of the following apply: *its source code is not available or is only available under an incompatible license *its code cannot be adapted to a new target platform *its existing code has become too difficult to handle and extend *the task of debugging it seems too complicated *the programmer finds it difficult to understand its source code *developers learn new techniques or wish to do a big feature overhaul which requires much change *developers learn that new codes written may extend content options that can fix or overwrite previous problems *the programming language of the source code has to be changed Risks Several software engineers, such as Joel Spolsky h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String (computer Programming)
In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). A string is generally considered as a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding. ''String'' may also denote more general arrays or other sequence (or list) data types and structures. Depending on the programming language and precise data type used, a variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. When a string appears literally in source code, it is known as a string literal or an anonymous string. In formal languages, which are used in mathematical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Security Exploit
An exploit (from the English verb ''to exploit'', meaning "to use something to one’s own advantage") is a piece of software, a chunk of data, or a sequence of commands that takes advantage of a bug or vulnerability to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic (usually computerized). Such behavior frequently includes things like gaining control of a computer system, allowing privilege escalation, or a denial-of-service (DoS or related DDoS) attack. In lay terms, some exploit is akin to a 'hack'. Classification There are several methods of classifying exploits. The most common is by how the exploit communicates to the vulnerable software. A ''remote exploit'' works over a network and exploits the security vulnerability without any prior access to the vulnerable system. A ''local exploit'' requires prior access to the vulnerable system and usually increases the privileges of the person running the exploit past tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canonical Form
In mathematics and computer science, a canonical, normal, or standard form of a mathematical object is a standard way of presenting that object as a mathematical expression. Often, it is one which provides the simplest representation of an object and which allows it to be identified in a unique way. The distinction between "canonical" and "normal" forms varies from subfield to subfield. In most fields, a canonical form specifies a ''unique'' representation for every object, while a normal form simply specifies its form, without the requirement of uniqueness. The canonical form of a positive integer in decimal representation is a finite sequence of digits that does not begin with zero. More generally, for a class of objects on which an equivalence relation is defined, a canonical form consists in the choice of a specific object in each class. For example: * Jordan normal form is a canonical form for matrix similarity. *The row echelon form is a canonical form, when one con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canonicalization
In computer science, canonicalization (sometimes standardization or normalization) is a process for converting data that has more than one possible representation into a "standard", "normal", or canonical form. This can be done to compare different representations for equivalence, to count the number of distinct data structures, to improve the efficiency of various algorithms by eliminating repeated calculations, or to make it possible to impose a meaningful sorting order. Usage cases Filenames Files in file systems may in most cases be accessed through multiple filenames. For instance in Unix-like systems, the string "/./" can be replaced by "/". In the C standard library, the function realpath() performs this task. Other operations performed by this function to canonicalize filenames are the handling of /.. components referring to parent directories, simplification of sequences of multiple slashes, removal of trailing slashes, and the resolution of symbolic links. Cano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passwd (file)
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons. When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password is considered to be correct, and the user is authenticated. In theory, it is possible for two different passwords to produce the same hash. However, cryptographic hash functions are designed in such a way that finding any password that produces the same hash is very difficult and practically infeasible, so if the produced hash matches the stored one, the user can be authenticated. The pas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cesar Cerrudo
Cesar, César or Cèsar may refer to: Arts, entertainment, and media * ''César'' (film), a 1936 film directed by Marcel Pagnol * ''César'' (play), a play by Marcel Pagnolt * César Award, a French film award Places * Cesar, Portugal * Cesar River, a river within the Magdalena Basin of Colombia * Cesar River, Chile * Cesar Department, Colombia Other uses * César (grape), an ancient red wine grape from northern Burgundy * French ship ''César'' (1768), ship of the line, destroyed 1782 * Recife Center for Advanced Studies and Systems (C.E.S.A.R), in Brazil * Cesar, a brand of dog food manufactured by Mars, Incorporated People with the given name * César (footballer, born May 1979), César Vinicio Cervo de Luca, Brazilian football centre-back * César (footballer, born July 1979), Clederson César de Souza, Brazilian football winger * César Alierta (born 1945), Spanish businessman * César Augusto Soares dos Reis Ribela (born 1995), Brazilian footballer * César Azpil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Kornbrust
Alexander is a male given name. The most prominent bearer of the name is Alexander the Great, the king of the Ancient Greek kingdom of Macedonia who created one of the largest empires in ancient history. Variants listed here are Aleksandar, Aleksander and Aleksandr. Related names and diminutives include Iskandar, Alec, Alek, Alex, Alexandre, Aleks, Aleksa and Sander; feminine forms include Alexandra, Alexandria, and Sasha. Etymology The name ''Alexander'' originates from the (; 'defending men' or 'protector of men'). It is a compound of the verb (; 'to ward off, avert, defend') and the noun (, genitive: , ; meaning 'man'). It is an example of the widespread motif of Greek names expressing "battle-prowess", in this case the ability to withstand or push back an enemy battle line. The earliest attested form of the name, is the Mycenaean Greek feminine anthroponym , , (/ Alexandra/), written in the Linear B syllabic script. Alaksandu, alternatively called ''Alakasandu' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Litchfield
David Litchfield (born 1975) is a British security expert and The Director of Information Security Assurance for Apple. Anne Saita, writing for ''Information Security'' magazine, called him along with his brother Mark Litchfield, "World's Best Bug Hunters" in December, 2003. Computer security Litchfield has found hundreds of vulnerabilities in many popular products, among which the most outstanding discoveries in products by Microsoft, Oracle and IBM. At the Blackhat Security Briefings in July 2002 he presented some exploit code to demonstrate a buffer overflow vulnerability he had discovered in Microsoft's SQL Server 2000. Then six months later, on 25 January 2003, persons unknown used the code as the template for the SQL Slammer Worm. After several years in vulnerability research, Litchfield made a move into Oracle forensics and has documented how to perform a forensic analysis of a compromised database server in a series of white papers – Oracle Forensics Parts 1 to 6. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Privilege Escalation
Privilege escalation is the act of exploiting a bug, a design flaw, or a configuration oversight in an operating system or software application to gain elevated access to resources that are normally protected from an application or user. The result is that an application with more privileges than intended by the application developer or system administrator can perform unauthorized actions. Background Most computer systems are designed for use with multiple user accounts, each of which has abilities known as privileges. Common privileges include viewing and editing files or modifying system files. Privilege escalation means users receive privileges they are not entitled to. These privileges can be used to delete files, view private information, or install unwanted programs such as viruses. It usually occurs when a system has a bug that allows security to be bypassed or, alternatively, has flawed design assumptions about how it will be used. Privilege escalation occurs in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SQL Injection
In computing, SQL injection is a code injection technique used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker). SQL injection must exploit a security vulnerability in an application's software, for example, when user input is either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and unexpectedly executed. SQL injection is mostly known as an attack vector for websites but can be used to attack any type of SQL database. SQL injection attacks allow attackers to spoof identity, tamper with existing data, cause repudiation issues such as voiding transactions or changing balances, allow the complete disclosure of all data on the system, destroy the data or make it otherwise unavailable, and become administrators of the database server. In a 2012 study, it was observed that the avera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
