Bugtraq mailing list archives
Re: Possible issue with Cisco on-line help?
From: lnapier () CISCO COM (Lisa Napier)
Date: Tue, 9 May 2000 13:30:13 -0700
Hi Fernando, I confirmed this behavior, and found some history on why we did things this way. The original intent of showing a limited subset of commands at the "show ?" help command was to simplify the command line help subsystem. When user typed the command "show ?", we intended to provide them a list of only the most used and useful commands at that level. To allow customers to see all the commands available at that level, the command "terminal full-help" was implemented in October of 1993. The intent was not security related at all, but simply an attempt to provide only the 'useful' commands to the users who were supposed to be at that prompt and at that level, rather than having them scroll through several screens of available but not very useful commands. So, rather than being an inadvertent mistake in the parser, this is actually how the product was designed. I will be updating our white papers on securing routers to include the recommendation of setting the default user privilege level to 0, and ensuring that only commands that are explicitly permitted to be run by un-enabled users are set to priv level 0. Thanks much for your work on this Fernando, Lisa Napier Product Security Incident Response Team Cisco Systems http://www.cisco.com/warp/public/707/sec_incident_response.shtml At 12:04 PM 05/04/2000 +0000, Fernando Montenegro wrote:
Hi! I have received information from Matti Saarinen <mjs () cc tut fi> explaining how the on-line help can be configured to show all the commands available (see below). This explains the apparent lack of authorization control over the "show" options. It seems that the only issue left is that there is so much information available from the non-enabled account.I would think that, on account of that, the recommendation for "jailing" the user still applies, though. Cheers, Fernando Extracts from the message received from Matti Saarinen <mjs () cc tut fi>:Router2>show ?> backup Backup status cef Cisco Express Forwarding clock Display the system clock dialer Dialer parameters and statistics flash: display information about flash: file>systemhistory Display the session command history>...>Notice that we did not see an "access-lists" option, sothehelp system thinks we should not be able to run it...Yes, you cannot normally see access-lists option in the output of the help system. router>sh ? alps Alps information atm ATM information backup Backup status[cut] But when you enable full help the access-lists option is there with many others: router>terminal full-help router>sh ? access-expression List access expression access-lists List access lists adjacency Adjacent nodes aliases Display alias commands alps Alps information arp ARP table async Information on terminal lines used as router interfaces atm ATM information backup Backup status And the privilege level was 1 the whole time: router>sh priv Current privilege level is 1
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