Timing Analysis of Keystrokes and Timing Attacks on SSH
by Dawn Xiaodong Song, David Wagner, and Xuqing Tian
USENIX, August 2001, Washington DC, USA
https://www.usenix.org/conference/10th-usenix-security-symposium/timing-analysis-keystrokes-and-timing-attacks-ssh https://www.usenix.org/legacy/events/sec01/full_papers/song/song.pdf
This paper discuses timing attacks against the SSH protocol that can be used to determine what was typed in an SSH session by measuring the latency between packets containing keystrokes.
| Notes |
|---|
| SSH |
| block cipher |
| padding |
| keystroke packets are sent as they are typed in SSH. |
| hidden Markov model |
| Herbivore |
| https://www.openwall.com/articles/SSH-Traffic-Analysis |
| “Herbivore can speed up exhaustive search for passwords by a factor of 50” |
| telnet, rlogin, ftp are insecure networking protcols, used broadly into the 00’s |
| Ethernet |
| meta keys |
| users’ typing follows a stable pattern |
| n-Viterbi algorithm |
| SSH1 SSH2 |
| pgp |
| su |
| nested ssh sessions |
| Gaussian distribution |
| Gaussian modeling |
| histogram |
| statistics |
| statistical learning |
| timing is measured between keystroke pairs |
| entropy of english is 0.6 - 1.3 bits per character |
| standard deviation |
| finite-state stochastic process |
| probability |
| likelihood |
| googletest |
| Krocher timing attack https://krishnadk.hashnode.dev/kochers-timing-attack |
| https://paulkocher.com/doc/TimingAttacks.pdf |
| Paul Krocher - SPECTRE vulnerabilities |
| Trostle timing attack |
| adding “chaff”/dummy packets to obscure keystroke timings |
| sending ssh packets at a flat rate to obscure keystroke timings |
| Solar Designer |
https://objects.lib.uidaho.edu/etd/pdf/Pereyda_idaho_0089M_10181.pdf
| References |
|---|
| Steven M. Bellovin. Packets found on an internet. - Computer Communications Review |
| S. Bleha, C. Slivinksy, and B. Hussein. Computer-access security systems using keystrokes dynamics. In IEEE Transactions on Pattern Analysis and Machine Intelligence PAMI-12, volume 12, December 1990 |
| William R. Cheswick and Steven M. Bellovin. Firewalls and Internet Security – Repelling the Wily Hacker. Professional Computing Series. Addison-Wesley, 1994. ISBN 0-201-63357-4. |
| Solar Designer and Dug Song. Passive analysis of SSH (secure shell) traffic. Openwall advisory OW-003, March 2001. |
| R. Gaines, W. Lisowski, S. Press, and N. Shapiro. Authentication by keystroke timing: Some preliminary results. Technical Report Rand report R-256-NSF, Rand corporation, 1980. |
| Simson Garfinkel and Gene Spafford. Practical UNIX & Internet Security. O’Reilly & Associates, 1996. |
| Rick Joyce and Gopal Gupta. Identity authentication based on keystroke latencies. Communications of the ACM, 33(2):168 – 176, February 1990. |
| P. Kocher. Cryptanalysis of Diffie-Hellman, RSA, DSS, and other cryptosystems using timing attacks. In Advances in cryptology, CRYPTO ’95, pages 171–183. Springer-Verlag, 1995. |
| G. Leggett and J. Williams. Verifying identity via keystroke characteristics. International Journal of Man-Machine Studies, 28(1):67–76, 1988. |
| G. Leggett, J. Williams, and D. Umphress. Verification of user identity via keystroke characteristics. Human Factors in Management Information Systems, 1989. |
| Fabian Monrose and Avi Rubin. Authentication via keystroke dynamics. In Proceedings of the 4th ACM Conference on Computer and Communications Security, pages 48–56, April 1997. |
| F. Monrose, M. K. Reiter, and S. Wetzel. Password hardening based on keystroke dynamics. In Proceedings of the 6th ACM Conference on Computer and Communications Security, November 1999. |
| National Bureau of Standards. Specification for the Data Encryption Standard. Federal Information Processing Standards Publication 46 (FIPS PUB 46), January 1977. |
| U. S. National Institute of Standards and Technology (NIST). Data Encryption Standard (DES). Draft Federal Information Processing Standards Publication 46-3 (FIPS PUB 46-3), January 1999. |
| J. A. Robinson, V. M. Liang, J. A. Chambers, and C. L. MacKenzie. Computer user verification using login string keystroke dynamics. IEEE Transactions on System, Man, and Cybernetics, 28(2), 1998. |
| Stuart Russell and Peter Norvig. Artificial Intelligence, A modern approach. Prentice Hall, 1995. |
| Claude E. Shannon. Prediction and Entropy of Printed English. Bell Sys. Tech. J (3), 1950 |
| IETF Secure Shell Working Group (SECSH). http://www.ietf.org/html. charters/secsh-charter.html, 2001 |
| Jonathan Trostle. Timing attacks against trusted path. In IEEE Symposium on Security and Privacy, 1998. |
| D. Umphress and J. Williams. Identity verification through keyboard characteristics. International Journal of Man-Machine Studies, 23(3):263–273, 1985. |
| T. Ylonen, ¨ T. Kivinen, M. Saarinen, T. Rinne, and S. Lehtinen. SSH authentication protocol. Internet Draft, Internet Engineering Task Force, May 2000. Work in progress. |
| T. Ylonen, ¨ T. Kivinen, M. Saarinen, T. Rinne, and S. Lehtinen. SSH protocol architecture. Internet Draft, Internet Engineering Task Force, May 2000. Work in progress. |
| Tatu Ylonen. ¨ SSH – Secure Login Connections over the Internet. In Sixth USENIX Security Symposium, San Jose, California, July 1996 |
| Philip R. Zimmermann. The Official PGP User’s Guide. MIT Press, Cambridge, MA, USA, 1995. ISBN 0-262-74017-6. |
| Yin Zhang and Vern Paxson. Detecting backdoors. In Proc. of 9th USENIX Security Symposium, August 2000. |
| Yin Zhang and Vern Paxson. Detecting stepping stones. In Proc. of 9th USENIX Security Symposium, August 2000. |