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Vulnerability Assessment Details

OpenSSH Reverse DNS Lookup bypass

Vulnerability Assessment Summary
Checks for the remote SSH version

Detailed Explanation for this Vulnerability Assessment

You are running OpenSSH-portable 3.6.1 or older.

There is a flaw in this version which may permit a possible hacker to
bypass the access controls set by the administrator of this server.

OpenSSH features a mechanism which can restrict the list of
hosts a given user can log from by specifying a pattern
in the user key file (ie: *.mynetwork.com would let a user
connect only from the local network).

However there is a flaw in the way OpenSSH does reverse DNS lookups.
If a possible hacker configures his DNS server to send a numeric IP address
when a reverse lookup is performed, he may be able to circumvent
this mechanism.

Solution : Upgrade to OpenSSH 3.6.2 when it comes out
Network Security Threat Level: Low

Networks Security ID: 7831

Vulnerability Assessment Copyright: This script is Copyright (C) 2003-2006 Tenable Network Security

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