Secure Software Development Flashcards
SDLC
Software Development Life Cycle:
An organized process of developing a secure application throughout the life of the project
Waterfall Model
Project Planning > Requirements > Analysis > Design > Coding > Testing > Deployment
SDLC Phases
Planning & Analysis Software/Systems Design Implementation Testing Integration Deployment Maintenance
Agile
Software development is performed in time-boxed or small increments to allow more adaptivity to change
DevOps
Software development and information technology operations
SDLC Principles: Defense in Depth
Layering of security controls is more effective and secure than relying on a single control
SDLC Principles: Never Trust User Input
Any input that is received from a user should undergo input validation prior to allowing it to be utilized by an application
SDLC Principles: Minimize Attack Surface
Reduce the amount of code used by a program, eliminate unneeded functionality, and require authentication prior to running additional plugins
SDLC Principles: Create Secure Defaults
Default installations should include secure configurations instead of requiring an administrator or user to add in additional security
SDLC Principles: Authenticity & Integrity
Applications should be deployed using code signing to ensure the program is not changed inadvertently or maliciously prior to delivery to an end user
SDLC Principles: Fail Securely
Applications should be coded to properly conduct error handling for exceptions in order to fail securely instead of crashing
SDLC Principles: Rely on Trusted SDKs
SDKs must come from trusted source to ensure no malicious code is being added
Black-box Testing
Occurs when a tester is not provided with any information about the system or program prior to conducting the test
White-box Testing
Occurs when a tester is provided full details of a system including the source code, diagrams, and user credentials in order to conduct the test
Gray-box Testing
(Combination of Black & White-box)
The tester partially understands the application’s internal working structure
Structured Exception Handling (SEH)
Structured Exception Handling:
Provides control over what the application should do when faced with a runtime or syntax error
Input Validation
Applications verify that information received from a user matches a specific format or range of values
Static Analysis
Source code of an application is reviewed manually or with automatic tools without running the code
Dynamic Analysis
Analysis and testing of a program occurs while it is being executed or run
Fuzzing
Injection of randomized data into a software program in an attempt to find system failures, memory leaks, error handling issues, and improper input validation
Backdoors
Code placed in computer programs to bypass normal authentication and other security mechanisms
Backdoors are a poor coding practice and should not be utilized
Directory Traversal
Method of accessing unauthorized directories by moving through the directory structure on a remote server
Arbitrary Code Execution
Occurs when an attacker is able to execute or run commands on a victim computer (not remotely)
RCE
Remote Code Execution:
Occurs when an attacker is able to execute or run commands on a remote computer
Buffer Overflow
Occurs when a process stores data outside the memory range allocated by the developer
Buffer
A temporary storage area that a program uses to store data
Over 85% of data breaches were caused by a buffer overflow
Stack
Reserved area of memory where the program saves the return address when a function call instruction is received
“Smash the Stack”
Occurs when an attacker fills up the buffer with NOP so that the return address may hit a NOP and continue on until it finds the attacker’s code to run
Address Space Layout Randomization
Method used by programmers to randomly arrange the different address spaces used by a program or process to prevent buffer overflow exploits
XSS (3 Types)
Cross-Site Scripting:
Occurs when an attacker embeds malicious scripting commands on a trusted website
Stored/Persistent
Attempts to get data provided by the attacker to be saved on the web server by the victim
Isn’t just reflected, data is stored in DB/Server then sent to the user from where it’s stored
Injects anyone that views the content (ex: if Youtube allowed JS in comments)
Reflected
Attempts to have a non-persistent effect activated by a victim clicking a link on the site
Input (JS) is reflected back into the response
DOM-based
Attempt to exploit the victim’s web browser
User’s input lands inside a dangerous part of JS code (happens on client-side)
Prevent XSS with output encoding and proper input validation
XSRF/CSRF
Cross-Site Request Forgery:
Occurs when an attacker forces a user to execute actions on a web server for which they are already authenticated
One domain is forging a request to another to modify a value
Example: You’re on a website and click a link to an external site, but it deletes your account on the original site
Prevent XSRF with tokens, encryption, XML file scanning, and cookie verification
SQL Injection
Attack consisting of the insertion or injection of an SQL query via input data from the client to a web application
SQL injection is prevented through input validation and using least privilege when accessing a database
If you see ` OR 1=1; on the exam, it’s an SQL injection
Injection Attack
Insertion of additional information or code through data input from a client to an application
SQL
HTML
XML
LDAP
Most common type is an SQL injection
XML Vulnerabilities
XML data submitted without encryption or input validation is vulnerable to spoofing, request forgery, and injection of arbitrary code
XML Bomb (Billion Laughs Attack)
XML encodes entities that expand to exponential sizes, consuming memory on the host and potentially crashing it
XML Eternal Entity (XXE)
An attack that embeds a request for a local resource
To prevent XML vulnerabilities from being exploited, use proper input validation
Race Conditions
A software vulnerability when the resulting outcome from execution processes is directly dependent on the order and timing of certain events, and those events fail to execute in the order and timing intended by the developer
A race condition vulnerability is found where multiple threads are attempting to write a variable or object at the same memory location
Race Conditions: Dereferencing
A software vulnerability that occurs when the code attempts to remove the relationship between a pointer and the thing it points to.
Race conditions are difficult to detect and mitigate
Race conditions can also be used against databases and file systems
Time of Check to Time of Use (TOCTTOU)
The potential vulnerability that occurs when there is a change between when an app checked a resource and when the app used the resource
Preventing Race Conditions/TOCTTOU
Develop applications to not process things sequentially if possible
Implement a locking mechanism to provide app with exclusive access
Design Vulnerabilities: Insecure Components
Any code that is used or invoked outside the main program development process
Code Reuse
Third-party Library
Software Development Kit (SDK)
Design Vulnerabilities: Insufficient Logging/Monitoring
Any program that does not properly record or log detailed enough information for an analyst to perform their job
Logging and monitoring must support your use case and answer who, what, when, where, and how
Design Vulnerabilities: Weak of Default Configurations
Any program that uses ineffective credentials or configurations, or one in which the defaults have not be changed for security
Many applications choose to simply run as root or as a local admin
Permissions may be too permissive on files or directories due to weak configurations
Utilize scripted installations and baseline configuration templates to secure applications during installation
LDAP Injections
LDAP typically stores authentication info (user/pass)
Attacker makes malformed queries to pull more info than they’re supposed to (or to bypass authentication)
Usually via URLs or input fields
Example:
Normal Query
http://www.CVexample.com/people_search.aspx?name=Sam)(zone=public)
Manipulated Query
http://www.CVexample.com/people_search.aspx?name=Sam)(zone=*)
SSL Stripping/HTTP Downgrade
Combines an on-path with a downgrade attack (attacker sits between client/server)
Attacker modifies data between victim & web server
Done via: Proxy server, ARP spoofing, or rogue AP
Dead Code
Section of source code of a program which is executed but whose result is never used in any other computation.
Add security vulnerability
OWASP
Open Web Application Security Project:
An online community that produces freely-available articles, methodologies, documentation, tools, and technologies in the field of web application security
