Jim Manico: Developer Top 10 Core Controls, web application security @ OWASP Göteborg

Top 10 Web Security Controls March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 1

(1) Query Parameterization (PHP PDO) $stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (:name, :value)"); $stmt->bindParam(':name', $name); $stmt->bindParam(':value', $value); March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 2

Query Parameterization (.NET) SqlConnection objConnection = new SqlConnection(_ConnectionString); objConnection.Open(); SqlCommand objCommand = new SqlCommand( "SELECT * FROM User WHERE Name = @Name AND Password = @Password", objConnection); objCommand.Parameters.Add("@Name", NameTextBox.Text); objCommand.Parameters.Add("@Password", PasswordTextBox.Text); SqlDataReader objReader = objCommand.ExecuteReader(); if (objReader.Read()) { ... March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 3

Query Parameterization (Java) double newSalary = request.getParameter(“newSalary”) ; int id = request.getParameter(“id”); PreparedStatement pstmt = con.prepareStatement("UPDATE EMPLOYEES SET SALARY = ? WHERE ID = ?"); pstmt.setDouble(1, newSalary); pstmt.setInt(2, id); Query safeHQLQuery = session.createQuery("from Inventory where productID=:productid"); safeHQLQuery.setParameter("productid", userSuppliedParameter); March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 4

Query Parameterization (Ruby) # Create Project.create!(:name => 'owasp') # Read Project.all(:conditions => "name = ?", name) Project.all(:conditions => { :name => name }) Project.where("name = :name", :name => name) # Update project.update_attributes(:name => 'owasp') # Delete Project.delete(:name => 'name') March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 5

Query Parameterization (Cold Fusion) <cfquery name="getFirst" dataSource="cfsnippets"> SELECT * FROM #strDatabasePrefix#_courses WHERE intCourseID = <cfqueryparam value=#intCourseID# CFSQLType="CF_SQL_INTEGER"> </cfquery> March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 6

Query Parameterization (PERL) my $sql = "INSERT INTO foo (bar, baz) VALUES ( ?, ? )”; my $sth = $dbh->prepare( $sql ); $sth->execute( $bar, $baz ); March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 7

XSS: Why so Serious? Session hijacking Site defacement Network scanning Undermining CSRF defenses Site redirection/phishing Load of remotely hosted scripts Data theft Keystroke logging March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 8

Danger: Multiple Contexts Browsers have multiple contexts that must be considered! March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 9

XSS in HTML Attributes < i n p u t typ e = "te x t" n am e = "c o m m e n ts ” valu e = "U N T R U S T E D D AT A"> < i n p u t typ e = "te x t" n am e = "c o m m e n ts " valu e = "h e llo " o n m o u s e o ve r= "/* fi re attac k * /">  Attackers can add event handlers:  onMouseOver  onLoad  onUnLoad  etc… March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 10

XSS in Source Attribute  User input often winds up in src attribute  Tags such as < i m g s rc = ""> < i fram e s rc = "">  Example Request: h ttp ://e x am p le .c o m /vi e w I m ag e ? i m ag e n am e = m ym ap .jp g  Attackers can use javascript:/*attack*/ in src attributes March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 11

URL Parameter Escaping  Escape all non alpha-num characters with the %HH format < a h re f= “/s e arc h ?d ata= U N T R U S T E D D AT A”>  Be careful not to allow untrusted data to drive entire URL’s or URL fragments  This encoding only protects you from XSS at the time of rendering the link  Treat DATA as untrusted after submitted March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 12

XSS in the Style Tag  Applications sometimes take user data and use it to generate presentation style U R L p aram e te r w ri tte n w i th i n s tyle tag  Consider this example: h ttp ://e x am p le .c o m /vi e w D o c u m e n t?b ac k g ro u n d = w h i te March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 13

CSS Pwnage Test Case < d i v s tyle = "w i d th : < % = te m p 3% > ;"> M o u s e o ve r < / d i v> temp3 = ESAPI.encoder().encodeForCSS("expression(alert (String.fromCharCode (88,88,88)))"); < d i v s tyle = "w i d th : e x p re s s i o n 2 8 ale rt2 8 S tri n g 2 e fro m C h arC o d e 2 0 2 8 882 c 882 c 882 9 2 9 2 9 ;"> M o u s e o ve r < /d i v>  Pops in at least IE6 and IE7. li s ts .o w as p .o rg /p i p e rm ai l/o w as p -e s ap i /2 009- F e b ru ary/000405 .h tm l March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 14

Javascript Context  Escape all non alpha-num characters with the xHH format <script>var x='U N T R U S T E D D AT A';</script>  You're now protected from XSS at the time data is assigned  What happens to x after you assign it? March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 15

Best Practice: DOM Based XSS Defense  Untrusted data should only be treated as displayable text  JavaScript encode and delimit untrusted data as quoted strings  Use document.createElement("…"), element.setAttribute("…","value"), element.appendChild(…), etc. to build dynamic interfaces  Avoid use of HTML rendering methods  Understand the dataflow of untrusted data through your JavaScript code. If you do have to use the methods above remember to HTML and then JavaScript encode the untrusted data  Avoid passing untrusted data to eval(), setTimeout() etc.  Don’t eval() JSON to convert it to native JavaScript objects. Instead use JSON.toJSON() and JSON.parse()  Run untrusted scripts in a sandbox (ECMAScript canopy, HTML 5 frame sandbox, etc) March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 16

(2) XSS Defense by Data Type and Context Data Type Context Defense String HTML Body HTML Entity Encode String HTML Attribute Minimal Attribute Encoding String GET Parameter URL Encoding String Untrusted URL URL Validation, avoid javascript: URL’s, Attribute encoding, safe URL verification String CSS Strict structural validation, CSS Hex encoding, good design HTML HTML Body HTML Validation (JSoup, AntiSamy, HTML Sanitizer) Any DOM DOM XSS Cheat sheet Untrusted JavaScript Any Sandboxing JSON Client parse time JSON.parse() or json2.js Safe HTML Attributes include: align, alink, alt, bgcolor, border, cellpadding, cellspacing, class, color, cols, colspan, coords, dir, face, height, hspace, ismap, lang, marginheight, marginwidth, multiple, nohref, noresize, noshade, nowrap, ref, rel, rev, rows, rowspan, scrolling, shape, span, summary, tabindex, title, usemap, valign, value, vlink, vspace, width March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 17

Attacks on Access Control Vertical Access Control Attacks  A standard user accessing administration functionality  “Privilege Escalation” Horizontal Access Control attacks  Same role, but accessing another user's private data Business Logic Access Control Attacks  Abuse of workflow March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 18

Best Practice: Code to the Activity if (AC.hasAccess(ARTICLE_EDIT, NUM)) { //execute activity } Code it once, never needs to change again Implies policy is persisted/centralized in some way Requires more design/work up front to get right March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 19

Best Practice: Use a Centralized Access Controller In Presentation Layer if (ACL.isAuthorized(VIEW_LOG_PANEL)) { <h2>Here are the logs</h2> <%=getLogs();%/> } In Controller try (ACL.assertAuthorized(DELETE_USER)) { deleteUser(); } March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 20

(3) Access Control Positive Patterns Code to the activity, not the role Centralize access control logic Design access control as a filter Fail securely (deny-by-default) Apply same core logic to presentation and server- side access control decisions Server-side trusted data should drive access control Provide privilege and user grouping for better management Isolate administrative features and access March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 21

Anatomy of an CSRF Attack Consider a consumer banking application that contains the following form <form action=“https://bank.com/Transfer.asp” method=“POST” id=“form1”> <p>Account Num: <input type=“text” name=“acct” value=“13243”/></p> <p>Transfer Amt: <input type=“text” name=“amount” value=“1000” /></p> </form> <script>document.getElementById(‘form1’).submit(); </script> March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 22

(4) Cross Site Request Forgery Defenses Cryptographic Tokens Primary and most powerful defense. Randomness is your friend. Request that cause side effects should use (and require) the POST method Alone, this is not sufficient Require users to re-authenticate Amazon.com does this *really* well Double-cookie submit Decent defense, but no based on randomness, based on SOP March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 23

Authentication Dangers Weak password Login Brute Force Username Harvesting Session Fixation Weak or Predictable Session Plaintext or poor password storage Weak "Forgot Password” feature Weak "Change Password” feature Credential or session exposure in transit via network sniffing Session Hijacking via XSS March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 24

(5) Authentication Defenses  2FA  Develop generic failed login messages that do not indicate whether the user-id or password was incorrect  Enforce account lockout after a pre-determined number of failed login attempts  Force re-authentication at critical application boundaries edit email, edit profile, edit finance info, ship to new address, change password, etc.  Implement server-side enforcement of credential syntax and strength March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 25

(6) Forgot Password Secure Design  Require identity and security questions  Last name, account number, email, DOB  Enforce lockout policy  Ask one or more good security questions  http://www.goodsecurityquestions.com/  Send the user a randomly generated token via out-of-band method  email, SMS or token  Verify code in same web session  Enforce lockout policy  Change password  Enforce password policy March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 26

(7) Session Defenses  Ensure secure session ID’s 20+ bytes, cryptographically random Stored in HTTP Cookies Cookies: Secure, HTTP Only, limited path  Generate new session ID at login time To avoid session fixation  Session Timeout Idle Timeout Absolute Timeout Logout Functionality March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 27

(8) Clickjacking Defense  Standard Option: X-FRAME-OPTIONS Header // to prevent all framing of this content response.addHeader( "X-FRAME-OPTIONS", "DENY" ); // to allow framing of this content only by this site response.addHeader( "X-FRAME-OPTIONS", "SAMEORIGIN" );  Frame-breaking Script defense: <style id="antiClickjack">body{display:none}</style> <script type="text/javascript"> if (self == top) { var antiClickjack = document.getElementByID("antiClickjack"); antiClickjack.parentNode.removeChild(antiClickjack) } else { top.location = self.location; } </script> March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 28

(9a) Secure Password Storage public String hash(String plaintext, String salt, int iterations) throws EncryptionException { byte[] bytes = null; try { MessageDigest digest = MessageDigest.getInstance(hashAlgorithm); digest.reset(); digest.update(ESAPI.securityConfiguration().getMasterSalt()); digest.update(salt.getBytes(encoding)); digest.update(plaintext.getBytes(encoding)); // rehash a number of times to help strengthen weak passwords bytes = digest.digest(); for (int i = 0; i < iterations; i++) { digest.reset(); bytes = digest.digest(bytes); } String encoded = ESAPI.encoder().encodeForBase64(bytes,false); return encoded; } catch (Exception ex) { throw new EncryptionException("Internal error", "Error"); }} March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 29

(9b) Password Security Defenses Disab le Browser Autocomplete  <form AUTOCOMPLETE="off”>  <input AUTOCOMPLETE="off”> Pass word and form fields  Input type=password Additi onal password securityManico and Eoin Keary March 2012 Top Ten Controls v4.1 Jim Page 30

(10) Encryption in Transit (TLS)  Authentication credentials and session identifiers must me be encrypted in transit via HTTPS/SSL Starting when the login form is rendered Until logout is complete All other sensitive data should be protected via HTTPS!  https://www.ssllabs.com free online assessment of public facing server HTTPS configuration  https://www.owasp.org/index.php/Transport_Layer_Protection_ for HTTPS best practices March 2012 Top Ten Controls v4.1 Jim Manico and Eoin Keary Page 31

Jim Manico: Developer Top 10 Core Controls, web application security @ OWASP Göteborg

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