COMMAND
APC
SYSTEMS AFFECTED
APC web/snmp/telnet management
PROBLEM
'altomo' found following. Some APC products such as the symetra
offer the option of adding a management card to allow an admin
the ablilty to setup monitoring and notification. The card is
accessable by snmp, web interface, and telnet. Itseems that only
one telnet connection is allowed at a time.(problem 1). The
telnet sesssion is authenticated by a user/password method, if
the incorrect combination is entered 3 times no connections are
allowed for the defined lockout time. Min. 1 minute, max 10
minutes. (problem 2)
Problem 1
=========
Since only one connection is allowed to the telnet port an admin
could be kept from connecting. Easy to reproduce.
cat /dev/zero | nc ip-here 23 (ya ya dirty)
Problem 2
=========
Lock out period. Lock out periods are a good thing, we really do
like them. But when no one can connect its a bad thing. Since
the lockout period can not be set to 0 an attacker could take
advantage of this by sending 3 incorrect login attempts to the
unit and repeat every 60 secs using the minimal lockout time.
Even if the admin has lockout set to 10 minutes it will keep
repeating and work when it actually is enabled again.
Both of these are easy to reproduce.
DoS Code:
---
Content-Type: application/octet-stream; name="apcdos.pl"
Content-Transfer-Encoding: base64
Content-Disposition: inline; filename="apcdos.pl"
Content-MD5: F3KB1oBnhiW8zWzz9gvdVQ==
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ZyBrb25nIGRhbmdlciBkdW8KFromownerbugtraqSECURITYFOCUSCOMTueFeb2720540720
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-----
SOLUTION
Author contacted APC via email and informed they of what had been
found and asked if this was going to be addressed in the future.
The response received back was:
"At this time the security on the web card is at its highest
level. The only other suggestion is to make changes on the
firewall."
APC's responds is kinda true. Why would you want to have the
telnet port to your UPS open wide up to the world. These UPS
IP's should sit behind your DMZ and treat them as a internal
servers. Or atleast they should be on a private subnet, and Admin
have to logon to a box and hop over to the UPS private subnet.
BUT what about internal attackers? There are 2 ghetto style work
arounds of course.
1. leave web or snmp open to managed this product
2. put on a private network and have a linux box infront ssh
to linux box then telnet to apc.