From owner-freebsd-ports  Sat Nov  6 11:40: 4 1999
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Date: Sat,  6 Nov 1999 11:30:21 -0800 (PST)
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Subject: ports/14749: /usr/ports/security/ssh/ has remote buffer-overflow
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>Number:         14749
>Category:       ports
>Synopsis:       /usr/ports/security/ssh/ has remote buffer-overflow
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-ports
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Nov  6 11:40:00 PST 1999
>Closed-Date:
>Last-Modified:
>Originator:     N/A
>Release:        RELENG3
>Organization:
N/A
>Environment:
FreeBSD XXXXXX 3.3-STABLE FreeBSD 3.3-STABLE #6: Thu Sep 30 20:23
:42 PDT 1999     root@XXXXXXX:/usr/src/sys/compile/GARLIC  i386
>Description:
There appears to be an exploitable buffer-overrun in the SSH 1.2.27 version in ports, with the RSAREF implementation.  SSH 1.2.27 is seemingly no longer supported. 

It goes like that...
  sshd.c, do_connection at line 1513 gets a long number from the
remote side.  It proceeds to pass it into rsa_private_decrypt. 
rsa_private_decrypt (in rsaglue.c) has a ~200 byte buffer which can 
be overflowed, giving a SIGBUS or SIG 11.  It might take some talent
to overflow this because of the conversions.


>How-To-Repeat:

In ssh-1.2.27, modify your sshconnect.c, do_login, change every instance of SSH_SESSION_KEY_LENGTH to SSH_SESSION_KEY_LENGTH+500, and
comment out the call to a_public_encrypt (otherwise, you'd crash yourself). 
A true exploit would probably only encrypt some of the buffer, leaving
the rest to cause problems.

>Fix:
don't use static buffers here, or do a simple bounds check.


>Release-Note:
>Audit-Trail:
>Unformatted:


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