Bekijk Volledige Versie : New HP Jetdirect SNMP password vulnerability when using Web JetAdmin
Sven Pechler
03/03/03, 17:42
Hello,
During an analysis of some HP Jetdirect cards I discovered a security
issue that could lead to full access to a networked printer.
It looks like the vulnerability described in
http://www.securityfocus.com/bid/5331, but the OID is different and you
can only obtain one specific password.
It is also different from the password vulnerability described in
http://www.securityfocus.com/bid/3132
It applies to the following situation:
- Any operating system
-HP Jetdirect cards JetDirect 300X, (J3263A), JetDirect EX Plus (J2591A),
JetDirect 400N (J2552A, J2552B), JetDirect 600N (J3110A, J3111A, J3113A)
and older.
-The Jetdirect card is being managed from HP Web Jetadmin.
-A Web Jetadmin "device password" had been set on the JetDirect card.
(This password must be set from Web Jetadmin and has nothing to do with
the Telnet password or the SNMP Set community name)
In the above situation the Web Jetadmin device password is readable as
plain ASCII tekst from the JetDirect card using SNMP.
How to check your printers for this vulnerability:
Use an SNMP toolkit to read the following OID from your printer:
..iso.org.dod.internet.private.enterprises.hp.nm.s ystem.net-peripheral.net-
printer.generalDeviceStatus.gdPasswords
(In numerical format: .1.3.6.1.4.1.11.2.3.9.1.1.13.0)
An example on a Windows machine, using SNMPUTIL from the Windows Resource
kit:
C:\>snmputil get 131.155.120.118 public .1.3.6.1.4.1.11.2.3.9.1.1.13.0
Variable = .iso.org.dod.internet.private.enterprises.11.2.3.9 .1.1.13.0
Value = String
<0x41><0x42><0x43><0x44><0x55><0x56><0x3d><0x31><0x30><0x38><0
x3b><0x00><0x00><0x00><0x00> ..etc...
The resulting string reads in ASCII: ABCDEF=108;
The Web Jetadmin device password is the word before the '=' sign, in this
case: ABCDEF
How to protect your printer:
1. Keep the Web Jetadmin device password EMPTY (don't do this on
newer cards than the ones mentioned above)
2. Define a 'Set community name' instead
Additional means of protection (does not address the SNMP vulnerability):
3. Define a telnet password (do not keep it empty)
4. Create an 'allow list' from the Telnet console to restrict access
from defined IP-addresses
Sven Pechler
University of Technology Eindhoven
Faculty of Technology Management
Mike Kristovich
03/03/03, 23:13
Sven,
Unfortunately, if you do a scan of a few subnets, you're bound to find
quite a bit of open, unpassworded Jetdirect hosts. If you just scan for
port 23 and/or port 80, these Jetdirects pop up everywhere. Most of them
will not have a password set on them. You have this defined as #3 on your
"additional protection" list. It makes a very good point that most
administrations don't tend to pay attention to. This is a known issue, but
it still exists worldwide. The information provided will hopefully remind a
good number of people to go ahead and set the password now, before somebody
else does.
As you will see in the examples below, you can compromise an HP
Jetdirect via telnet quite easily. If the password is disabled (as it is on
most), you'll have instant administrative access. A similar interface can
be found on port 80 (WWW), but is java-driven almost entirely. Take a look
at the examples below to see how easily you can compromise via telnet.
Telnetting to port 23 will give you the following:
-------------------
HP JetDirect
Please type "?" for HELP, or "/" for current settings
>
-------------------
Typing "/" will give you the following:
===JetDirect Telnet Configuration===
Firmware Rev. : G.08.40
MAC Address : 00:X0:X0:cX:7X:Xf
Config By : USER SPECIFIED
IP Address : X.X.X.X
Subnet Mask : 255.255.255.0
Default Gateway : X.X.X.X
Syslog Server : Not Specified
Idle Timeout : 120 Seconds
Set Cmnty Name : Not Specified
Host Name : Not Specified
DHCP Config : Disabled
---> Passwd : Disabled
IPX/SPX : Enabled
DLC/LLC : Disabled
Ethertalk : Disabled
Banner page : Enabled
-------------------------
If you type "?" for help, you'll notice this line at the end.
Type passwd to change the password.
Type "passwd", and..
Enter Password[16 character max.; 0 to disable]: >
You now have complete control of the device, while locking out the "real"
administrator.
------------------
> Additional means of protection (does not address the SNMP vulnerability):
> 3. Define a telnet password (do not keep it empty)
#3 on the list you provided is extremely important. Remember to set a
password, or you're leaving the device open for public administration!
Thanks,
Mike Kristovich, Security Researcher
PivX Solutions, LLC
http://www.PivX.com
----- Original Message -----
From: "Sven Pechler" <helpdesk@tm.tue.nl>
To: <bugtraq@securityfocus.com>
Sent: Monday, March 03, 2003 10:25 AM
Subject: New HP Jetdirect SNMP password vulnerability when using Web
JetAdmin
>
>
> Hello,
>
> During an analysis of some HP Jetdirect cards I discovered a security
> issue that could lead to full access to a networked printer.
>
> It looks like the vulnerability described in
> http://www.securityfocus.com/bid/5331, but the OID is different and you
> can only obtain one specific password.
> It is also different from the password vulnerability described in
> http://www.securityfocus.com/bid/3132
>
>
> It applies to the following situation:
>
> - Any operating system
>
> -HP Jetdirect cards JetDirect 300X, (J3263A), JetDirect EX Plus (J2591A),
> JetDirect 400N (J2552A, J2552B), JetDirect 600N (J3110A, J3111A, J3113A)
> and older.
>
> -The Jetdirect card is being managed from HP Web Jetadmin.
>
> -A Web Jetadmin "device password" had been set on the JetDirect card.
> (This password must be set from Web Jetadmin and has nothing to do with
> the Telnet password or the SNMP Set community name)
>
> In the above situation the Web Jetadmin device password is readable as
> plain ASCII tekst from the JetDirect card using SNMP.
>
>
> How to check your printers for this vulnerability:
>
> Use an SNMP toolkit to read the following OID from your printer:
> .iso.org.dod.internet.private.enterprises.hp.nm.sy stem.net-peripheral.net-
> printer.generalDeviceStatus.gdPasswords
> (In numerical format: .1.3.6.1.4.1.11.2.3.9.1.1.13.0)
>
> An example on a Windows machine, using SNMPUTIL from the Windows Resource
> kit:
> C:\>snmputil get 131.155.120.118 public .1.3.6.1.4.1.11.2.3.9.1.1.13.0
> Variable = .iso.org.dod.internet.private.enterprises.11.2.3.9 .1.1.13.0
> Value = String
> <0x41><0x42><0x43><0x44><0x55><0x56><0x3d><0x31><0x30><0x38><0
> x3b><0x00><0x00><0x00><0x00> ..etc...
>
> The resulting string reads in ASCII: ABCDEF=108;
> The Web Jetadmin device password is the word before the '=' sign, in this
> case: ABCDEF
>
>
> How to protect your printer:
>
> 1. Keep the Web Jetadmin device password EMPTY (don't do this on
> newer cards than the ones mentioned above)
> 2. Define a 'Set community name' instead
>
> Additional means of protection (does not address the SNMP vulnerability):
> 3. Define a telnet password (do not keep it empty)
> 4. Create an 'allow list' from the Telnet console to restrict access
> from defined IP-addresses
>
>
>
> Sven Pechler
> University of Technology Eindhoven
> Faculty of Technology Management
>
snooper@satx.rr.com
03/03/03, 23:44
Sven,
I have been doing some research on the same issue, and it appears that
some of the new firmware versions from HP actually fix this
vulnerability by replacing the web server with a newer version that
doesn't rely on client-side java to verify the password.
The issue at hand stems from the fact that the web server in older
firmware versions (and some of the newer firmware versions) relied on
client-side java to validate the administrator login. This
implementation did not encrypt and send the password to the web server
to validate, but retrieved the password through snmp (read: plaintext)
from the printer and validated the login on the client side.
As far as the fixes go, neither of the fixes that you outlined will
remedy the situation:
1. If you set the snmp community string to anything other than the
default, 'internal' (the default for the JetAdmin Web Server) will still
work. The snmp community string of 'internal' is, as far as I have been
able to tell, unremovable. Once the snmp community strings have been
set to whatever non-default string you want, 'internal' still seems to
work.
2. If you do not set a password on the JetAdmin Web Server, anyone can
change the settings without authentication.
The best solution in this case is to disable the JetAdmin Web Server (if
you cannot upgrade the firmware to include the Web Server that isn't
written with client-side java) by typing 'ews-config: 0' at the telnet
prompt. Once this is done, the password can still be retrieved through
the snmp object you mentioned, however no access will be granted (make
sure your telnet password is different). If you upgrade the printer
firmware, an easy check to see if the new version is vulnerable is to
access the web server: if you see the old, mostly-blue colored page,
you're still vulnerable. The new web server will still reply to the
snmp request, but from what I've seen, it's always null (all 0x00, 0x00,...)
One more side note: in your example, the raw ascii string is actually
'ABCDUV' :)
Have you talked to HP about this?
Geoff
-----Original Message-----
From: Sven Pechler [mailto:helpdesk@tm.tue.nl]
Sent: Monday, March 03, 2003 9:26 AM
To: bugtraq@securityfocus.com
Subject: New HP Jetdirect SNMP password vulnerability when using Web
JetAdmin
Hello,
During an analysis of some HP Jetdirect cards I discovered a security
issue that could lead to full access to a networked printer.
It looks like the vulnerability described in
http://www.securityfocus.com/bid/5331, but the OID is different and you
can only obtain one specific password.
It is also different from the password vulnerability described in
http://www.securityfocus.com/bid/3132
It applies to the following situation:
- Any operating system
-HP Jetdirect cards JetDirect 300X, (J3263A), JetDirect EX Plus (J2591A),
JetDirect 400N (J2552A, J2552B), JetDirect 600N (J3110A, J3111A, J3113A)
and older.
-The Jetdirect card is being managed from HP Web Jetadmin.
-A Web Jetadmin "device password" had been set on the JetDirect card.
(This password must be set from Web Jetadmin and has nothing to do with
the Telnet password or the SNMP Set community name)
In the above situation the Web Jetadmin device password is readable as
plain ASCII tekst from the JetDirect card using SNMP.
How to check your printers for this vulnerability:
Use an SNMP toolkit to read the following OID from your printer:
..iso.org.dod.internet.private.enterprises.hp.nm.s ystem.net-peripheral.net-
printer.generalDeviceStatus.gdPasswords
(In numerical format: .1.3.6.1.4.1.11.2.3.9.1.1.13.0)
An example on a Windows machine, using SNMPUTIL from the Windows Resource
kit:
C:\>snmputil get 131.155.120.118 public .1.3.6.1.4.1.11.2.3.9.1.1.13.0
Variable = .iso.org.dod.internet.private.enterprises.11.2.3.9 .1.1.13.0
Value = String
<0x41><0x42><0x43><0x44><0x55><0x56><0x3d><0x31><0x30><0x38><0
x3b><0x00><0x00><0x00><0x00> ..etc...
The resulting string reads in ASCII: ABCDEF=108;
The Web Jetadmin device password is the word before the '=' sign, in this
case: ABCDEF
How to protect your printer:
1. Keep the Web Jetadmin device password EMPTY (don't do this on
newer cards than the ones mentioned above)
2. Define a 'Set community name' instead
Additional means of protection (does not address the SNMP vulnerability):
3. Define a telnet password (do not keep it empty)
4. Create an 'allow list' from the Telnet console to restrict access
from defined IP-addresses
Sven Pechler
University of Technology Eindhoven
Faculty of Technology Management