Night of the living vulnerabilities: forever-days of IoT

Video: https://www.youtube.com/watch?v=OIYoe32biNk

In a tribute to Romero's masterpiece, we examined the resurgence of vulnerabilities we all thought dead. As soon as a security expert looks at the firmware and code of IoT devices, 2017 may as well be 1997: format string bugs, basic stack overflows and hardcoded credentials arise. Zero-days are actually forever-days.
We looked at a number of real world cases of industrial and consumer IoT devices we tested and broke, and besides analyzing the most common and most outstanding findings, we will wonder why we seem unable to kill these pests once and forever.

Transcript

1. NIGHT OF THE LIVING VULNS Roberto Clapis, Stefano Zanero CODEMOTION MILAN - SPECIAL EDITION 10 – 11 NOVEMBER 2017
2. A tale of horror and hope in the land of IoT Starring: Roberto Clapis Security Engineer Secure Network Stefano Zanero Associate Professor Politecnico di Milano
3. ▪Smart hairbrush ▪Smart wine bottle ▪Smart egg tray ▪Smart salt shaker
4. ▪Smart Plugs ▪Smart Keychain ▪Smart Thermostat ▪Smart Irrigation Controllers
5. ▪Cooperative Robots ▪Insulin Pumps ▪Automotive ▪Surgical Robots
6. THREAT MODEL ▪Internet facing but not designed for it ▪Contains PII ▪Safety critical
7. WHAT ARE WE EXACTLY TALKING ABOUT?
8. FORMAT STRING IN THERMOSTAT
9. BUFFER OVERFLOW IN POS DEVICES
10. BUFFER OVERFLOW IN POS DEVICES This is an fgets()
11. SOMETIMES IOT DEVICES ARE NOT SMALL AND CUTE...
12. DEFAULT PASSWORDS NEVER DIE
13. DID YOU SAY CODE SIGNING? Any password works during boot No code signing or verification (!) What the... ?
14. ZOMBIE VULNERABILITY MATRIOSKA FTP RETR /command/whatever read system info FTP STOR /command/command execute “commands” e.g., shell reboot shell uas_disable With no/hardcoded credentials!
15. COPY-PASTA THAT SPAGHETTI CODE
16. 1980 CALLED, THEY WANT THEIR VULNS BACK
17. • Why are these vulns still alive? • What are the tools we can use? • To find out, and go beyond our own opinion, we brainstormed with tens of developers and openly twitter- stormed with the security community
18. WHY ARE THEY STILL ALIVE ▪ Lack of awareness ▪ A senior developer was completely puzzled by the potential security risks of strcpy ▪ Perception that security vulnerabilities happen only to "the web guys" ▪ Out of memory is cool again but no one knows it ▪ Old code and technical debt ▪ Time to market pressure ▪ The security community is not providing viable solutions
19. ▪ Stack overflow vulnerabilities "as if in the 90s" ▪ Often no memory segment protection ▪ No ASLR ▪ No W^X ▪ Grsec missing in action and... ▪ The default was until very recently --no_protect_stack (the opposite of all other architectures) for no reason at all!!! http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.d ui0491i/BCFGBAIC.html
20. ▪Lack of IDE tools ▪Lack of emulators for extensive testing ▪There are no "safe(r)" libraries ▪Most of the tools we (can) recommend either do not exist in embedded or are not usable by developers
21. ▪Fuzzing with AFL / libfuzzer ▪Compcert C ▪"Change language to..." ▪Address Sanitizer (no Linux/ARM yet) https://github.com/google/sanitiz ers/wiki/AddressSanitizer
22. ▪Let people choose their analysis tools ▪Advanced threat modeling/secure coding training for all developers ▪"Consider all inputs (including sensors) hostile, always"
23. ▪"Apply LangSec" ▪Look at the assembly output, especially on sensitive or crypto code. Unrealistic. ▪"Patch sbrk() to reboot rather than allowing malloc() to return 0"
24. ▪ Create or use some safe libraries, e.g. to handle type safety, integer expansion/truncation, etc. ▪ https://github.com/mbedded-ninja/MFixedPoint/ ▪ MISRA C and the JPL coding standard: ▪ https://yurichev.com/mirrors/C/JPL_Coding_Standard_C.pdf ▪ Simple cheat sheets and usable documentations: ▪ https://www.owasp.org/index.php/C-Based_Toolchain_Hardening_Cheat_Sheet ▪ https://github.com/intel/safestringlib/wiki/SDL-List-of-Banned-Functions ▪ https://scriptingxss.gitbooks.io/embedded-appsec-best-practices/ ▪ Don't reinvent the wheel (updates, graphics libraries) ▪ https://mender.io ▪ https://ugfx.io
25. ▪ Flawfinder ▪ Cppcheck: ▪ http://cppcheck.sourceforge.net ▪ Scitools: ▪ https://scitools.com/features ▪ Frama-C ▪ Clang Analyzer ▪ Enable stack protector
26. What if you inherit a codebase? ▪ Get any and all documentation left behind, are there patterns in the kinds of bugs being fixed? ▪ Check if there are good tests in place already ▪ Lint the code ▪ Start with static analysis tools ▪ Look for bad/incompletely commented sections and TODOs ▪ Seek for inputs and uses of untrusted data and follow the breadcrumbs ▪ Seek for custom crypto code and kill it with fire ▪ Don't be afraid of refactoring
27. ▪ For further information: ▪ https://www.amazon.com/Secure-Programming-Cookbook- Cryptography-Authentication/dp/0596003943 ▪ https://www.amazon.com/Secure-Coding-2nd-Software- Engineering/dp/0321822137 ▪ https://www.e-reading.club/bookreader.php/138815/Linden_- _Expert_C_Programming:_Deep_C_Secrets.pdf ▪ https://www.amazon.com/Safer-McGraw-Hill-International- Software-Engineering/dp/0077076400 ▪ http://www.cse.psu.edu/~pdm12/cse597g- f15/readings/cse597g-embedded_systems.pdf ▪ https://www.blackhat.com/presentations/bh-usa-04/bh-us-04- grand/grand_embedded_security_US04.pdf
28. CONCLUSIONS: WHY CAN'T WE HAVE NICE IOTHINGS ▪ Lack of Awareness ▪ Lack in Tools ▪ Lack in Processes ▪ We are not aiming for the head