Testing Python security PyCon IE

Python is a language that in a easy way allows to scale up from starter projects to complex applications for data processing and serving dynamic web pages. But as you increase complexity in your applications, it can be easy to introduce potential problems and vulnerabilities. In this talk, I will highlight the biggest problems we can find in python functions, how to use then in a secure way and tools and services that help you identify vulnerabilities in the python source code. These could be the main talking points:
-Introduction to secure programming in python.
-Introduce dangerous functions for code inyection and how we can solve this issues from a security point of view.
-Common attack vectors on Python applications like Remote Command Execution and SQL injection
-Best practices for avoid execution of malicious commands
-Tools that help us to protect and obfuscate our source code

Transcript

1. Testing python security PyconIE 2018 1 @jmortegac Testing Python Security José Manuel Ortega @jmortegac
2. Testing python security PyconIE 2018 2 @jmortegac • Develop Python scripts for automating security and pentesting tasks • Discover the Python standard library's main modules used for performing security-related tasks • Automate analytical tasks and the extraction of information from servers • Explore processes for detecting and exploiting vulnerabilities in servers • Use network software for Python programming • Perform server scripting and port scanning with Python • Identify vulnerabilities in web applications with Python • Use Python to extract metadata and forensics
3. Testing python security PyconIE 2018 3 @jmortegac jmortega.github.io
4. Testing python security PyconIE 2018 4 @jmortegac 1. Secure coding 2. Dangerous functions 3. Common attack vectors 4. Static analisys tools 5. Other security issues
5. Testing python security PyconIE 2018 5 @jmortegac Secure coding 1. Analysis of architectures involved 2. Review of implementation details 3. Verification of code logic and syntax 4. Operational testing (unit testing, white-box) 5. Functional testing (black-box)
6. Testing python security PyconIE 2018 6 @jmortegac Unsafe python components
7. Testing python security PyconIE 2018 7 @jmortegac Dangerous Python Functions
8. Testing python security PyconIE 2018 8 @jmortegac Security issues Here’s a list of handful of other potential issues to watch for: • Dangerous python functions like eval() • Serialization and deserialization objects with pickle • SQL and JavaScript snippets • API keys included in source code • HTTP calls to internal or external web services
9. Testing python security PyconIE 2018 9 @jmortegac Improper input/output validation
10. Testing python security PyconIE 2018 10 @jmortegac eval() eval(expression[, globals[, locals]])
11. Testing python security PyconIE 2018 11 @jmortegac eval() No globals
12. Testing python security PyconIE 2018 12 @jmortegac eval() eval("__import__('os').system('clear') ", {}) eval("__import__('os').system('rm -rf')", {})
13. Testing python security PyconIE 2018 13 @jmortegac eval() Refuse access to the builtins
14. Testing python security PyconIE 2018 14 @jmortegac eval()
15. Testing python security PyconIE 2018 15 @jmortegac Serialization and Deserialization with Pickle WARNING: pickle or cPickle are NOT designed as safe/secure solution for serialization
16. Testing python security PyconIE 2018 16 @jmortegac Serialization and Deserialization with Pickle
17. Testing python security PyconIE 2018 17 @jmortegac Serialization and Deserialization with Pickle
18. Testing python security PyconIE 2018 18 @jmortegac Serialization and Deserialization with Pickle
19. Testing python security PyconIE 2018 19 @jmortegac Serialization and Deserialization with Pickle
20. Testing python security PyconIE 2018 20 @jmortegac Security issues Overflow errors • The buffer overflow • The integer or arithmetic overflow >> print xrange(2**63) Traceback (most recent call last): File "<stdin>", line 1, in <module> OverflowError: Python int too large to convert to C long >>> print range(2**63) Traceback (most recent call last): File "<stdin>", line 1, in <module> OverflowError: range() result has too many items
21. Testing python security PyconIE 2018 21 @jmortegac Input injection attacks
22. Testing python security PyconIE 2018 22 @jmortegac Command Injection @app.route('/menu',methods =['POST']) def menu(): param = request.form [ ' suggestion '] command = ' echo ' + param + ' >> ' + ' menu.txt ' subprocess.call(command,shell = True) with open('menu.txt','r') as f: menu = f.read() return render_template('command_injection.html', menu = menu)
23. Testing python security PyconIE 2018 23 @jmortegac Command Injection @app.route('/menu',methods =['POST']) def menu(): param = request.form [ ' suggestion '] command = ' echo ' + param + ' >> ' + ' menu.txt ' subprocess.call(command,shell = False) with open('menu.txt','r') as f: menu = f.read() return render_template('command_injection.html', menu = menu)
24. Testing python security PyconIE 2018 24 @jmortegac Command Injection
25. Testing python security PyconIE 2018 25 @jmortegac shlex module
26. Testing python security PyconIE 2018 26 @jmortegac PyExecCmd
27. Testing python security PyconIE 2018 27 @jmortegac Common attack vectors on web applications OWASP TOP 10: A1 Injection A2 Broken Authentication and Session Management A3 Cross-Site Scripting (XSS) A4 Insecure Direct Object References A5 Security Misconfiguration A6 Sensitive Data Exposure A7 Missing Function Level Access Control A8 Cross-Site Request Forgery (CSRF) A9 Using Components with Known Vulnerabilities A10 Unvalidated Redirects and Forwards
28. Testing python security PyconIE 2018 28 @jmortegac SQL Injection @app.route('/filtering') def filtering(): param = request.args.get('param', 'not set') Session = sessionmaker(bind = db.engine) session = Session() result = session.query(User).filter(" username ={} ".format(param)) for value in result: print(value.username , value.email) return ' Result is displayed in console.'
29. Testing python security PyconIE 2018 29 @jmortegac Prevent SQL injection attacks Prevent SQL injection attacks • NEVER concatenate untrusted inputs in SQL code. • Concatenate constant fragments of SQL (literals) with parameter placeholders. • cur.execute("SELECT * FROM students WHERE name= '%s';" % name) • c.execute("SELECT * from students WHERE name=(?)" , name)
30. Testing python security PyconIE 2018 30 @jmortegac Prevent SQL injection attacks
31. Testing python security PyconIE 2018 31 @jmortegac XSS from flask import Flask , request , make_response app = Flask(__name__) @app.route ('/XSS_param',methods =['GET ]) def XSS(): param = request.args.get('param','not set') html = open('templates/XSS_param.html ').read() resp = make_response(html.replace('{{ param}}',param)) return resp if __name__ == ' __main__ ': app.run(debug = True)
32. Testing python security PyconIE 2018 32 @jmortegac XSS Server Side Template Injection (SSTI)
33. Testing python security PyconIE 2018 33 @jmortegac XSS
34. Testing python security PyconIE 2018 34 @jmortegac XSS
35. Testing python security PyconIE 2018 35 @jmortegac Automated security testing Automatic Scanning tools: • SQLMap: Sql injection • XSScrapy: Sql injection and XSS Source Code Analysis tools: • Bandit: Open Source and can be easily integrated with Jenkins CI/CD
36. Testing python security PyconIE 2018 36 @jmortegac XSScrapy https://github.com/DanMcInerney/xsscrapy
37. Testing python security PyconIE 2018 37 @jmortegac SQLMap
38. Testing python security PyconIE 2018 38 @jmortegac SQLMap
39. Testing python security PyconIE 2018 39 @jmortegac Bandit
40. Testing python security PyconIE 2018 40 @jmortegac Bandit
41. Testing python security PyconIE 2018 41 @jmortegac Bandit Test plugins
42. Testing python security PyconIE 2018 42 @jmortegac Bandit Test plugins
43. Testing python security PyconIE 2018 43 @jmortegac Bandit Test plugins
44. Testing python security PyconIE 2018 44 @jmortegac Bandit Test plugins
45. Testing python security PyconIE 2018 45 @jmortegac Bandit Test plugins
46. Testing python security PyconIE 2018 46 @jmortegac Bandit Test plugins
47. Testing python security PyconIE 2018 47 @jmortegac Bandit Test plugins SELECT %s FROM derp;” % var “SELECT thing FROM ” + tab “SELECT ” + val + ” FROM ” + tab + … “SELECT {} FROM derp;”.format(var)
48. Testing python security PyconIE 2018 48 @jmortegac Syntribos Buffer Overflow Command Injection CORS Wildcard Integer Overflow LDAP Injection SQL Injection String Validation XML External Entity Cross Site Scripting (XSS) Regex Denial of Service (ReDoS)
49. Testing python security PyconIE 2018 49 @jmortegac Other security issues CPython vulnerabilities
50. Testing python security PyconIE 2018 50 @jmortegac Other security issues Insecure packages – acqusition (uploaded 2017-06-03 01:58:01, impersonates acquisition) – apidev-coop (uploaded 2017-06-03 05:16:08, impersonates apidev-coop_cms) – bzip (uploaded 2017-06-04 07:08:05, impersonates bz2file) – crypt (uploaded 2017-06-03 08:03:14, impersonates crypto) – django-server (uploaded 2017-06-02 08:22:23, impersonates django-server-guardian-api) – pwd (uploaded 2017-06-02 13:12:33, impersonates pwdhash) – setup-tools (uploaded 2017-06-02 08:54:44, impersonates setuptools) – telnet (uploaded 2017-06-02 15:35:05, impersonates telnetsrvlib) – urlib3 (uploaded 2017-06-02 07:09:29, impersonates urllib3) – urllib (uploaded 2017-06-02 07:03:37, impersonates urllib3)
51. Testing python security PyconIE 2018 51 @jmortegac Other security issues
52. Testing python security PyconIE 2018 52 @jmortegac Interesting links https://github.com/jmortega/testing_python_security
53. Testing python security PyconIE 2018 53 @jmortegac Interesting links https://security.openstack.org/#bandit-static-analysis-for-python https://security.openstack.org/guidelines/dg_use-subprocess-securely.html https://security.openstack.org/guidelines/dg_avoid-shell-true.html https://security.openstack.org/guidelines/dg_parameterize-database-querie s.html https://security.openstack.org/guidelines/dg_cross-site-scripting-xss.html https://security.openstack.org/guidelines/dg_avoid-dangerous-input-parsin g-libraries.html
54. Testing python security PyconIE 2018 54 @jmortegac Q&A Q & A