LISA 2001 Abstract
ScanSSH - Scanning the Internet for SSH Servers
Niels Provos and Peter Honeyman, University of
SSH is a widely used application that provides secure remote
login. It uses strong cryptography to provide authentication and
confidentiality. The IETF SecSH working group is developing SSH v2, an
improved SSH protocol that fixes cryptographic and design flaws in the
SSH v1 protocol. SSH v2 compatible server software is widespread.
Recently discovered security flaws make it critically important to
find vulnerable SSH servers and update them. In this paper, we
describe a method to determine with good precision how many servers
supporting the various protocol versions have been deployed on the
We describe the design and implementation of ScanSSH, a scanner
that probes SSH servers for their software version, and discuss the
results of scanning the Internet and our local networks for several
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