security in nodejs applications

NODE.JSSECURE CODING WITH

SECURE CODING WITH NODE.JS

OBJECTIVE

▸ The purpose of the following micro-course is learning by examples the major security flaws in code in NodeJS, possible solutions and good security practices.


INDEX


OWASP TOP 10 WITH 1 PICTURE


CORRESPONDENCIA CON OWASP TOP 10


VULNERABLE NODE.JS PROJECT

▸ https://github.com/cr0hn/vulnerable-node

https://github.com/cr0hn/vulnerable-node

https://github.com/cr0hn/vulnerable-node

A1 - 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. OWASP TOP 10

A1 - INJECTION

TEXTO

CODE INJECTION: DEFINITION▸ Those application points with input information, usually

from the user, which must be treated as untrusted by default.

▸ Assimilate and understand the expression: This code smells injection

A1 - INJECTION :: SQL INJECTION (1/5)

SQL INJECTION

function do_auth(username, password) { var db = pgp(config.db.connectionString);

var q = "SELECT * FROM users WHERE name = '" + username + "' AND password ='" + password + "';";

return db.one(q);}

/model/auth.js:4


SQL INJECTION

function do_auth(username, password) { var db = pgp(config.db.connectionString);

var q = "SELECT * FROM users WHERE name = '" + username + "' AND password ='" + password + "';";

return db.one(q);}

/model/auth.js:4


SQL INJECTION - ATTACK (1/2)


SQL INJECTION - ATTACK (2/2)


SQL INJECTION - SOLUTION

Prepared statement

A1 - INJECTION :: LOG INJECTION (1/3)

LOG INJECTION

router.post('/login/auth', function(req, res) {

var user = req.body.username; var password = req.body.password; var returnurl = req.body.returnurl;

logger.error("Tried to login attempt from user = " + user);

/model/login.js:25


LOG INJECTION - ATTACK (1/2)


LOG INJECTION - ATTACK (2/2)


LOG INJECTION - SOLUTION

Use a logging framework, adding variables as parametersIf you can’t use a framework, remove CR & LR

A1 - INJECTION :: EVIL REGEX (1/4)

EVIL REGEX - EXPLANATIONRegex: ^(a+)+$

Denial Of System (DoS)


EVIL REGEX

var re = /^([a-zA-Z0-9])(([\-.]|[_]+)?([a-zA-Z0-9]+))*(@){1}[a-z0-9]+[.]{1}(([a-z]{2,3})|([a-z]{2,3}[.]{1}[a-z]{2,3}))$/

if (!re.test(cart.mail)){ throw new Error("Invalid mail format");}

/routers/products.js:120


EVIL REGEX - ATTACK

30 seconds

▸ https://www.owasp.org/index.php/Regular_expression_Denial_of_Service_-_ReDoS


EVIL REGEX - SOLUTION

Use regex as simple as you can

Check each regex before go to production

https://www.owasp.org/index.php/Regular_expression_Denial_of_Service_-_ReDoS


A2 - 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.

OWASP TOP 10

A2 - BROKEN AUTHENTICATION AND SESSION MANAGEMENT

A2 - BROKEN AUTHENTICATION AND SESSION MANAGEMENT :: COOKIES (1/3)

COOKIES

app.use(session({ secret: 'ñasddfilhpaf78h78032h780g780fg780asg780dsbovncubuyvqy', cookie: { secure: false, maxAge: 99999999999 }}));

/model/app.js:43


COOKIES


COOKIES - SOLUTION

Enable HTTP-Only

Limite expire time of cookie

A3 - CROSS-SITE SCRIPTINGXSS 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.OWASP TOP 10

A3 - CROSS-SITE SCRIPTING

A3 - CROSS-SITE SCRIPTING (1/4)

XSS

router.get('/products/search', function(req, res, next) {

var url_params = url.parse(req.url, true).query; var query = url_params.q;

db_products.search(query) .then(function (data) {

res.render('search', { in_query: query, products: data }); })



XSS

router.get('/products/search', function(req, res, next) {

var url_params = url.parse(req.url, true).query; var query = url_params.q;

db_products.search(query) .then(function (data) {

res.render('search', { in_query: query, products: data }); })



XSS - ATTACK


XSS - SOLUTION

▸ https://github.com/mdevils/node-html-entities

HTML Entities

https://github.com/mdevils/node-html-entities

A4 - INSECURE DIRECT OBJECT REFERENCESA 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.

OWASP TOP 10

A4 - INSECURE DIRECT OBJECT REFERENCES


INSECURE DIRECT OBJECT REFERENCES (1/2)

router.all('/products/buy', function(req, res, next) { cart = { mail: params.mail, address: params.address, ship_date: params.ship_date, phone: params.phone, product_id: params.product_id, product_name: params.product_name, username: req.session.user_name, price: params.price.substr(0, params.price.length - 1)} db_products.purchase(cart)



INSECURE DIRECT OBJECT REFERENCES (2/2)

function purchase(cart) { var db = pgp(config.db.connectionString); var q = "INSERT INTO purchases(mail, product_name, user_name, product_id, address, phone, ship_date, price) VALUES('" + cart.mail + "', '" + cart.product_name + "', '" + cart.username + "', '" + cart.product_id + "', '" + cart.address + "', '" + cart.ship_date + "', '" + cart.phone + "', '" + cart.price + "');"; return db.one(q);}

/model/products.js:34

• User ownership check?• Price check?


INSECURE DIRECT OBJECT REFERENCES - ATTACK (1/2)


INSECURE DIRECT OBJECT REFERENCES - SOLUTION

Check database & object references

A6 - SENSITIVE DATA EXPOSUREMANY 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. OWASP TOP 10

A6 - SENSITIVE DATA EXPOSURE

A6 - SENSITIVE DATA EXPOSURE (1/4)

SENSITIVE DATA EXPOSURE

router.post('/login/auth', function(req, res) { var returnurl = req.body.returnurl;

auth(user, password)

}) .catch(function (err) { res.redirect("/login?returnurl=" + returnurl + "&error=" + err.message); });

/routers/login:39


SENSITIVE DATA EXPOSURE - ATTACK (1/3)

A8 - CROSS-SITE REQUEST FORGERYA 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.OWASP TOP 10

A8 - CROSS-SITE REQUEST FORGERY

A8 - CROSS-SITE REQUEST FORGERY (1/6)

CROSS-SITE REQUEST FORGERY

router.all('/products/buy', function(req, res, next) { cart = { mail: params.mail, address: params.address, ship_date: params.ship_date, phone: params.phone, product_id: params.product_id, product_name: params.product_name, username: req.session.user_name, price: params.price.substr(0, params.price.length - 1) } db_products.purchase(cart) .catch(function (err) { return res.json({message: "Product purchased correctly"}); });

/routers/products:89



router.all('/products/buy', function(req, res, next) { cart = { mail: params.mail, address: params.address, ship_date: params.ship_date, phone: params.phone, product_id: params.product_id, product_name: params.product_name, username: req.session.user_name, price: params.price.substr(0, params.price.length - 1) } db_products.purchase(cart) .catch(function (err) { return res.json({message: "Product purchased correctly"}); });

/routers/products:89

Token?



Buy by GET Request

No token


CROSS-SITE REQUEST FORGERY - ATTACK


CROSS-SITE REQUEST FORGERY - SOLUTION

Use POST requests for actions that modifies the system.

Use a unique token (CSRF Token) for each requests that modify the system.

A10 - UNVALIDATED REDIRECTS AND FORWARDSWEB 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.

OWASP TOP 10

A10 - UNVALIDATED REDIRECTS AND FORWARDS

A10 - UNVALIDATED REDIRECTS AND FORWARDS (1/4)

UNVALIDATED REDIRECTS AND FORWARDS


auth(user, password) .then(function (data) { if (returnurl == undefined || returnurl == ""){ returnurl = "/"; }

res.redirect(returnurl); })

/routers/login.js:36


UNVALIDATED REDIRECTS AND FORWARDS


auth(user, password) .then(function (data) { if (returnurl == undefined || returnurl == ""){ returnurl = "/"; }

res.redirect(returnurl); })

/routers/login.js:36


UNVALIDATED REDIRECTS AND FORWARDS - ATTACK


UNVALIDATED REDIRECTS AND FORWARDS - SOLUTION

Only allow relative to domain redirection

White list for redirections


REFERENCIAS▸ OWASP Top 10: https://www.owasp.org/index.php/Top_10_2013-Top_10 ▸ NodeJS Security check list:

https://blog.risingstack.com/node-js-security-checklist/ ▸ Evil regex:


▸ Detect potentially evil regex: https://github.com/substack/safe-regex

https://www.owasp.org/index.php/Top_10_2013-Top_10

https://blog.risingstack.com/node-js-security-checklist/



https://github.com/substack/safe-regex

security in nodejs applications

Software