Defects in Multistage Login Mechanisms Some applications use elaborate login mechanisms involving multiple stages. The server receives the two parameters in the query string newsid and lang and uses their values to determine what content should be presented to the user. Coverage includes data storage, cryptography, transport layers, data leakage, injection attacks, runtime manipulation, security controls, and cross-platform apps, with vulnerabilities highlighted and detailed information on the methods hackers use to get around standard security. Reverse Engineering Because ActiveX controls are typically written in native languages like C and C++, they cannot be trivially decompiled back to source code in the way that Java applets can be. Another example arises where the application presents different functionality to different categories of users for example, anonymous users, authenticated regular users, and administrators.
Even if the intermediaries on a particular network are believed to be trusted, it is safer to use secure transport mechanisms when passing sensitive data over it. If not, try supplying an additional parameter containing the username, using the same parameter name as is used in the main login form. The divergent behavior described arises because many web servers map specific file extensions to particular server-side components. Not only does it provide network security recommendations but it teaches you how to use black-hat tools such as oclHashcat, Loki, Burp Suite, Scapy, Metasploit, and Kali to actually test the security concepts learned. This chapter takes a brief look at how web applications have evolved and the many benefits they provide. A list of enumerated usernames can be used as the basis for various subsequent attacks, including password guessing, attacks on user data or sessions, or social engineering.
Insecure Distribution of Credentials Many applications employ a process in which credentials for newly created accounts are distributed to users out-of-band of their normal interaction with the application for example, via post or email. If this process is not handled carefully, then an attacker may be able to construct crafted input that succeeds in smuggling malicious data through the validation mechanism. When this is the case, the same components often appear within numerous other web applications on the Internet, which you can inspect to understand how the component functions. Irvine and his colleagues at the University of Plymouth. Because the attacker may target multiple usernames, the developer decides to store the number of failed attempts in an encrypted cookie, blocking any request if the number of failed attempts exceeds five. When you are attacking a web application, you should invest a significant amount of attention in the various authentication-related functions that it contains. Test Predictability of Auto-Generated Credentials 4.
There is currently little indication that the problem factors described previously are going to go away in the near future. Many applications can handle various browser configurations, and you may reach different content and code paths within the application. As with Java, obfuscation techniques have been devised in an attempt to hinder decompilation attacks. Some web server software includes a facility for administrators to set an arbitrary value for the Server header. For example, the application could concatenate the product code and price, encrypt the result as a single item, and then validate that the encrypted string submitted with an order actually matches the product being ordered. In other cases, the application stores the state information on the client side rather than the server, usually in encrypted form to prevent tampering. Overview of This Book The focus of this book is highly practical.
For example, an application may contain administrative functionality that deletes users, shuts down a database, restarts the server, and the like. Written by a team of highly experienced computer security experts,the handbook provides hands-on tutorials exploring a range ofcurrent attack methods. Forgotten Password Functionality Like password change functionality, mechanisms for recovering from a forgotten password situation often introduce problems that may have been avoided in the main login function, such as username enumeration. If you have read and understood all of the vulnerabilities and techniques described in this book, you can use this methodology as a complete checklist and work plan when carrying out an attack against a web application. When users followed hyperlinks, they navigated around the set of files created by the author, requesting each file via its name within the directory tree residing on the server. The server can use the entity tag to determine whether the browser may use its cached copy of the resource. It is a simple protocol that was originally developed for retrieving static text-based resources, and has since been extended and leveraged in various 35 70779c03.
See Chapter 14 for further ways in which the application may disclose information about itself. See Chapter 12 for further details. If a user does not make a request for a given period, then the session is ideally expired, as in Figure 2-2. Arguably, web application security is today the most significant battleground between attackers and those with computer resources and data to defend, and it is likely to remain so for the foreseeable future. We look at various common defects in the generation and transmission of session tokens, and describe the steps you can take to discover and exploit these.
Test for Function-Specific Input Vulnerabilities 712 8. Throughout this evolution, compromises of prominent web applications have remained in the news, and there is no sense that a corner has been turned and that these security problems are on the wane. Most applications are developed in-house, and many by developers who have little understanding of the security problems that may arise in the code they are producing. Please click button to get the browser hacker s handbook book The Mac Hacker S Handbook. Your choice to read Ios Hackers Handbook as one of your reading books, can be your proper book to read now. This is most commonly encountered in the names of static resources, rather than dynamic scripts. Is that your real hobby? The majority of sites on the web are in fact applications see Figure 1-2.
You can prefer to choose other book; but, it doesn't matter if you attempt to make this book as your reading choice. Test for Proxy Functionality 11. This is a trend that has been replicated in other areas of software security. These can be used in attacks against databases, but it may be a requirement that the application should permit anyone to register under their real name. This book dives deep into security procedures you should follow to avoid being exploited. Test for Path Traversal 7. It may be that some of the submissions are superfluous and are not actually processed by the application.
Any security controls implemented on the client side, such as input validation checks, can be easily circumvented. You'll then use that information to gain entry to the device or to perform other actions, such as dumping encryption keys and firmware. Wiley also publishes its books in a variety of electronic formats. Network administrators are familiar with the idea of preventing their users from visiting malicious web sites, and end users themselves are gradually becoming more aware of this threat. In the typical case, a user supplies her username and password, and the application must verify that these items are correct. Ralf-Philipp Weinmann holds a PhD in cryptography and has an extensive security background.
Developed by Sun Microsystems, it lends itself to multi-tiered and load-balanced architectures, and is well suited to modular development and code reuse. The flow of interesting information was oneway, from server to browser. Identifying Server-Side Functionality It is often possible to infer a great deal about server-side functionality and structure, or at least make an educated guess, by observing clues that the application discloses to the client. The function may be exploitable to send arbitrary messages to any recipient, and any of the fields may also be vulnerable to email header injection see Chapter 9. Find out how hackers gain access, overtake network devices, script and inject malicious code, and plunder Web applications and browsers. Every item of data received from the client should be regarded as tainted and potentially malicious. The authors of this book have tested hundreds of web applications in recent years.