In this article, I’m explaining the concept of security in node.js.

Being lightweight and efficient, Node.js is rapidly becoming a platform of choice for building fast, scalable, data-intensive, modern web applications. However, when used as a web server, the platform design choices and technologies used in it pose unique security challenges. Developing stable and resilient web applications on this platform is therefore very dependent on programmers.

On the one hand, impact level of several security threats is amplified on Node.js platform and server side JavaScript due its inherent characteristics. On the other hand, Node.js community lacks awareness, experience, and learning resources to effectively address such challenges on this relatively young platform.

With Node.js having become a critical cog at places such as PayPal and Wal-Mart, developers need to be mindful of securing their Node.js applications, technologists are advising.

The server-side JavaScript platform is now being used to protect the likes of financial transactions and other enterprise client data, said Adam Baldwin, chief security officer at security consulting firm ^Lift Security. Node.js shares security issues with its client-side brother, JavaScript, as well with other platforms, Baldwin said. "The core of Node is JavaScript, so Node inherits any concerns there might be with JavaScript. However, the execution context of V8, the JavaScript engine Node uses, is entirely different than a browser because it executes on the server. That difference adds some unique surface area [for attacks].

Mark Stuart, a senior UI engineer at PayPal, advises developers to use good security defaults and scanning of modules. "Node is still JavaScript, so eval and all the terrible things on the client side still exist on the server side," Stuart said. (The eval function evaluates code represented as a string but poses the risk of running malicious code.)

The importance of security on Node.js has led to formation of the Node Security Project, headed by Baldwin, which wants to audit NPMs (Node packaged modules). Developers need to actively address common security issues in their code, using resources such as the *OWASP (Open Web Application Security Project) Top 10, which includes cross-site scripting, cross-site request forgery, security misconfiguration, and unvalidated redirects and forwards.

OWASP (Open Web Application Security Project) 

1.    Injection

Injection flaws, such as SQL, OS, and LDAP injection occur when untrusted data is sent to an interpreter as part of a command or query. The attacker’s hostile data can trick the interpreter into executing unintended commands or accessing data without proper authorization. 

2.    Broken Authentication and Session Management 

Application functions related to authentication and session management are often not implemented correctly, allowing attackers to compromise passwords, keys, or session tokens, or to exploit other implementation flaws to assume other users’ identities.

3.    Cross-Site Scripting 

XSS flaws occur whenever an application takes untrusted data and sends it to a web browser without proper validation or escaping. XSS allows attackers to execute scripts in the victim’s browser which can hijack user sessions, deface web sites, or redirect the user to malicious sites. 

4.    Insecure Direct Object Reference 

A direct object reference occurs when a developer exposes a reference to an internal implementation object, such as a file, directory, or database key. Without an access control check or other protection, attackers can manipulate these references to access unauthorized data. 

5.    Security Misconfiguration 

Good security requires having a secure configuration defined and deployed for the application, frameworks, application server, web server, database server, and platform. Secure settings should be defined, implemented, and maintained, as defaults are often insecure. Additionally, software should be kept up to date. 

6.    Sensitive Data Exposure 

Many web applications do not properly protect sensitive data, such as credit cards, tax IDs, and authentication credentials. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data deserves extra protection such as encryption at rest or in transit, as well as special precautions when exchanged with the browser. 

7.    Missing Function Level access Control 

Most web applications verify function level access rights before making that functionality visible in the UI. However, applications need to perform the same access control checks on the server when each function is accessed. If requests are not verified, attackers will be able to forge requests in order to access functionality without proper authorization. 

8.    Cross Site Request Forgery (CSRF) 

A CSRF attack forces a logged-on victim’s browser to send a forged HTTP request, including the victim’s session cookie and any other automatically included authentication information, to a vulnerable web application. This allows the attacker to force the victim’s browser to generate requests the vulnerable application thinks are legitimate requests from the victim. 

9.    Using Components with Known Vulnerabilities 

Components, such as libraries, frameworks, and other software modules, almost always run with full privileges. If a vulnerable component is exploited, such an attack can facilitate serious data loss or server takeover. Applications using components with known vulnerabilities may undermine application defenses and enable a range of possible attacks and impacts. 

10.    Invalidated Redirects and Forwards 

Web applications frequently redirect and forward users to other pages and websites, and use untrusted data to determine the destination pages. Without proper validation, attackers can redirect victims to phishing or malware sites, or use forwards to access unauthorized pages.

Here give the common security options in the node.js through the OLWASP.