TLS-Attacker V2.2 And The ROBOT Attack

We found out that many TLS implementations are still vulnerable to different variations of a 19-year old Bleichenbacher's attack. Since Hanno argued to have an attack name, we called it ROBOT: https://robotattack.org

Given the new attack variants, we released a new version of TLS-Attacker 2.2, which covers our vulnerabilities.

Bleichenbacher's attack from 1998

In 1998, Daniel Bleichenbacher discovered that the error messages given by SSL servers for errors in the PKCS #1 1.5 padding allow an adversary to execute an adaptive-chosen ciphertext attack. This attack also belongs to the category of padding oracle attacks. By performing the attack, the adversary exploits different responses returned by the server that decrypts the requests and validates the PKCS#1 1.5 padding. Given such a server, the attacker can use it as an oracle and decrypt ciphertexts.

We refer to one of our previous blog posts for more details.

OK, so what is new in our research?

In our research we performed scans of several well-known hosts and found out many of them are vulnerable to different forms of the attack. In the original paper, an oracle was constructed from a server that responded with different TLS alert messages. In 2014, further side-channels like timings were exploited. However, all the previous studies have considered mostly open source implementations. Only a few vulnerabilities have been found.

In our scans we could identify more than seven vulnerable products and open source software implementations, including F5, Radware, Cisco, Erlang, Bouncy Castle, or WolfSSL. We identified new side-channels triggered by incomplete protocol flows or TCP socket states.

For example, some F5 products would respond to a malformed ciphertext located in the ClientKeyExchange message with a TLS alert 40 (handshake failure) but allow connections to timeout if the decryption was successful. We could observe this behaviour only when sending incomplete TLS handshakes missing ChangeCipherSpec and Finished messages.

See our paper for more interesting results.

Release of TLS-Attacker 2.2

These new findings motivated us to implement the complete detection of Bleichenbacher attacks in our TLS-Attacker. Before our research, TLS-Attacker had implemented a basic Bleichenbacher attack evaluation with full TLS protocol flows. We extended this evaluation with shortened protocol flows with missing ChangeCipherSpec and Finished messages, and implemented an oracle detection based on TCP timeouts and duplicated TLS alerts. In addition, Robert (@ic0ns) added many fixes and merged features like replay attacks on 0-RTT in TLS 1.3.

You can find the newest version release here: https://github.com/RUB-NDS/TLS-Attacker/releases/tag/v2.2

TLS-Attacker allows you to automatically send differently formatted PKCS#1 encrypted messages and observe the server behavior:

$ java -jar Attacks.jar bleichenbacher -connect [host]:[port]

In case the server responds with different error messages, it is most likely vulnerable. The following example provides an example of a vulnerable server detection output:

14:12:42 [main] CONSOLE attacks.impl.Attacker - A server is considered vulnerable to this attack if it responds differently to the test vectors.
14:12:42 [main] CONSOLE attacks.impl.Attacker - A server is considered secure if it always responds the same way.
14:12:49 [main] CONSOLE attacks.impl.Attacker - Found a difference in responses in the Complete TLS protocol flow with CCS and Finished messages.
14:12:49 [main] CONSOLE attacks.impl.Attacker - The server seems to respond with different record contents.
14:12:49 [main] INFO  attacks.Main - Vulnerable:true

In this case TLS-Attacker identified that sending different PKCS#1 messages results in different server responses (the record contents are different).

Related posts

1. Kik Hack Tools
2. New Hack Tools
3. Pentest Tools Bluekeep
4. Hack Tools Mac
5. Pentest Tools Framework
6. Hacker Tools Apk
7. Android Hack Tools Github
8. Pentest Tools Review
9. Hacking Tools For Pc
10. Hacking Tools For Kali Linux
11. Hacking Tools Usb
12. Hacker Hardware Tools
13. Game Hacking
14. Hacker Hardware Tools
15. Hacker Tools For Ios
16. Termux Hacking Tools 2019
17. Hack Tools Online
18. Pentest Tools Find Subdomains
19. Hacking Tools For Pc
20. Hacker Tool Kit
21. Tools For Hacker
22. Top Pentest Tools
23. Pentest Tools Windows
24. Hacking Tools And Software
25. Usb Pentest Tools
26. Pentest Tools Alternative
27. Pentest Tools Port Scanner
28. Hacker Tools Apk Download
29. Beginner Hacker Tools
30. Pentest Tools Framework
31. Hack Tools 2019
32. Pentest Tools Linux
33. Nsa Hack Tools Download
34. Hacking Tools Free Download
35. World No 1 Hacker Software
36. Pentest Recon Tools
37. Easy Hack Tools
38. Tools Used For Hacking
39. Pentest Tools Website
40. Best Hacking Tools 2019
41. Hacking Tools Hardware
42. Pentest Tools Website
43. Hack Tool Apk
44. Hacker Tools Free
45. Tools Used For Hacking
46. Hacker Tools 2020
47. Hacker Tools
48. Tools 4 Hack
49. Pentest Automation Tools
50. Hack Tools For Mac
51. Hacker Tools Github
52. Hacking Tools Download
53. Ethical Hacker Tools
54. Pentest Tools Online
55. Hacking Tools For Kali Linux
56. Hack Tools For Games
57. Pentest Tools
58. Hack Tools For Mac
59. Hack Tools Online
60. Hack Tools For Games
61. Pentest Tools For Android
62. Hacking Tools For Windows Free Download
63. Hackers Toolbox
64. Tools For Hacker
65. New Hacker Tools