OWASP 2 Session Contents Secure Code Characteristics Costs of Insecure Coding Threats to Code Secure Coding – General Principles Secure Coding – C and C++ Secure Coding – ASP.NET Secure Coding – Java Summary
OWASP 3 Defining Secure Coding Secure code must have the following properties SECURESECURE eamless ognizant of attacks asy to Understand nobtrusive esilient rror Tolerant
OWASP 4 Genesis of a Secure Application Slide taken from Security Engineering for Software, Dimitry Averin “Secure” Application Robust Programming Practices Good design and coding practices Design and implementation of security features. From the Requirements
OWASP 6 Threats to Code We, the programmers Bad Inputs (and Outputs) API Abuse Environment and Configuration Time and State
OWASP 7 Secure Coding – General Principles Validate inputs and outputs FLTR principle – Format, Length, Type, Range Reduce attack surface Running Code Entry Points (UI, ports, files, database, API calls) Reduce Privilege Operate at least privilege Open files/registry with required access rights Don’t write data in protected portions of the Operating System Apply Defense-in-depth Use gatekeeper paradigm Use APIs correctly String functions in C, Java,.NET Detect attacks and fail securely Phishing attacks Observe vendor’s recommendations
OWASP 8 Secure Coding – C and C++ Ensure that input is bounded – Prevents buffer overflow attacks char buf , memcpy(buf, user input, sizeof(user input)); Use variadic functions properly – Prevents format string attacks. printf(string) printf(“%s”,string) Check for integer overflow Ensure proper memory management Free data allocated on the heap/free store Avoid double free. Zero the pointer after the first free. Don’t mix new, delete with calloc,free Don’t store secrets in memory allocated with realloc Don’t forget the [ ] operator when deleting arrays
OWASP 9 Secure Coding – ASP.NET Don’t hard-code passwords in code or in Web.config / Machine.config Use aspnet_setreg.exe to store encrypted credentials in the registry. Validate input automatically Use validateRequest=true. Dynamic SQL Creation "SELECT * FROM items WHERE owner = '" + userName + "' AND itemname = '" + ItemName.Text + "'"; What if "name' OR 'a'='a" is passed for itemname? SELECT * FROM items WHERE owner = 'wiley' AND itemname = 'name' OR 'a'='a'; This maps to: SELECT * FROM items; Strong-name assemblies Use strong name as evidence for running assemblies Implement custom-error pages Make changes to the customErrors element in the Web.config. Configure to show detailed messages to local users only. Protect the ViewState Difference between using ViewStateEncryptionMode and SSL Set the HttpOnly option for cookies Prevents cookie-stealing scripts from reading the cookie
OWASP 10 Secure Coding – Java Avoid using inner classes Compiler translates the class and private variables to package scope access. Make private if required. Don’t compare classes by name. Use class equality instead. Malicious code could be running with the same name “Turn off” cloning by implementing clone() and making it final Attacker could instantiate your class without a constructor. “Turn off” serialisation by implementing writeObject() it and making it final Attacker could instantiate your class without a constructor. Seal your Java packages Prevents attackers from adding a class to the package Don’t return references to mutable objects Prevents attackers from changing the internal state of the object.
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