Visibilidad y detección de anomalías, Parte III

Following Part I and Part II, we will give another example why OT monitoring is necessary to have a look about what is happing in industrial environment. The last one finished if somebody connected their laptop to the network and then to a PLC. Today, we will see what happens if somebody, that is, a third party, contractor, support team, etc. carries out a task that requires that the PLC CPU goes to STOP and the process, as well.

Having said this, imagine a manufacturing plant in operation and during an intervention, an engineer puts online and accidentally sends a STOP command by STEP7 software or something similar that requires it. Obviously other scenario can be a targeted attack on an exposed controller in the network.

If this occurs a message will appear in “Alerts” tab with score of “10” in the risk column. In the picture below we can see the steps since the PC (IP: 10.10.201. 103)  establishes connection with the CPU (IP, 10.10.201.102) by COTP protocol and sends STOP and START requests.

If we open both alerts, we will find more information of the source, its MAC and IP address, port, protocol, direction and so on.

For troubleshooting purposes, we can download a trace of the packets to find more low-level information. After that we are able to open it with a network protocol analyzer.

This example has been done once Guardian is in Protecting mode. Before this, we have to configure the tool in a “Listening” mode to learn about the asset, protocol, communication, behavior, etc. to take a picture of the network and everything it contains.

If this event occurs during this time, the alert can be different. In this case the alert will be scored with 9 and 6 values, respectively. In the first example we have to remember that the device from which we send STOP command, has not been discovered during “Listening” phase so the tool will categorize the action with a higher value.

Until now, we talked about a concise command. But if the CPU is not protected as I wrote in previous posts.

So, we can go one step ahead and think that if we can reach the PLC to STOP and START the CPU we could access and download it’s program. If it can be done, we could modify it and then upload it again to cause error condition, alter variables, configure passwords in order to do not permit legitimate access, and so on. If this occurs, we could identify it as shown in the  following picture.

Today we have analyzed different actions that can be identified by Nozomi Guardian monitoring tool, it can help us to detect actions that could alter normal operations. After this, we could start to investigate how a machine tool, production line or other facility stops without any reason.

However, it is important to remark that before deploying any security monitoring tool, an organization should have carried out other technical actions. One of them is to separate and segregate IT and OT environments. To do so, it is necessary to identify, analyze and decide which traffic must be permitted to pass across our firewalls. Once it has be done, we will have the criteria to say if what is happening is a normal or abnormal behavior. In other words, if we do not identify and understand which workstations  can access  industrial equipment and implement a strict change management process, we will not have the capacity to discover the root cause of the alert. Does somebody act on a PLC? Is it an attack? Has the communication module  failed?

These tools are useful solution if we implement it on stable, well-know and secure OT network.

Thanks for reading the post! See you!!

Tools: Pss

Continuing with CPU Protection Part I and Part II I will present to you a tool that can help us to obtain the protection level password if it has been configured to control the access to a PLC CPU. In this case, a S7-300 SIEMENS controller.

Its name is PSS and the last version that I have found is 1.83. I have tested it on S7-300 but the author refers to other software over the ones known to be used for the same purpose such as STEP7, MicroWIN, WINCC, LOGO, etc. Please click the “?” symbol on the bottom right corner for more information.

Although some of them can be obsolete, we know that the lifecycle of OT devices and technologies is longer than IT equipment. For this reason, nowadays this tool can be  useful to audit or assess even when the software is very old.

To obtain it, we must select the directory which stores the project with the device that has a password configured.

After this, press right click button and select “Start Scan”.

Few seconds later we will see the password in plain text if it has been detected. In this case “ICS2020”.

Note if you change this password and assign another, apparently, it will still be stored because if you repeat the process you can see the previous ones.

This tool can be useful to recover forgotten passwords, but it can be used if somebody has unauthorized access to the system or media that stores them. It is not enough to establish a backup plan only; it is also necessary to protect the PLC program copies.

It does not make sense make a copy of programs or configuration files if somebody can access them and extract the passwords that restrict the capabilities to read and write on them.

As mentioned, we have to deploy different controls across our facilities, systems, networks, and apply all possible and available features that they bring us the security that we need. Keep always in mind that we can not introduce a higher risk that we are trying to mitigate and passwords can be cracked…

Thanks again for your time, see you in another one!

Stay tuned!

Visibilidad y detección de anomalías, Parte II

Siguiendo con la Parte I sobre “Visibilidad y detección de anomalías” comenzaremos un conjunto de ejemplos sobre cómo estas herramientas especializadas pueden ayudarnos a detectar ciertas situaciones.

Pongamos el primero. Un equipo ajeno a nuestra organización se conecta a la red de fábrica para llevar cabo una intervención por parte de un tercero. Esto es, un proveedor, una ingeniería. Algo muy habitual, y necesario, dado el grado de especialización que requiere la puesta en marcha o mantenimiento de maquinaria. ¿Y por qué digo necesario? Porque, salvo aspectos previamente acordados, esta tarea es llevada por los fabricantes de esa maquinaria.

Para ello se firman contratos de soporte que garantizan tiempos de respuesta, intervenciones programadas según necesidades, etc.. Y claro está, deberán de utilizar sus propios equipos. Los mismos donde tienen instalado el software y herramientas necesarias para hacer su trabajo y que como sabemos el precio de las licencias no suele ser especialmente económico como para que asuma el coste el propietario cuando él lo que contrata es un servicio.

Por ello, y otras razones es que esta situación es inevitable en muchos entornos y asumir que un equipo del que no sabemos a priori de su estado de protección, uso se le ha dado, a qué redes se ha conectado, software instalado, entre otras; es inevitable.

Dado que este equipo no ha sido registrado en el “período de aprendizaje” una vez conectado a la red y gracias a la replicación de tráfico a través del puerto espejo es que Nozomi Guardian detecta que tanto MAC como IP, genera una alerta categorizada como “10”.

Si accedemos al detalle de este podremos ver de una manera desglosada todas las acciones que ha intentado llevar a cabo.

En la parte inferior, además, vendrá representada de manera gráfica las IPs, protocolos y sentidos contra los que se quiere establecer comunicaciones. Esto aporta un grado de intuitividad y simplicidad importante cara a interpretar la información, lo cual ayuda a la persona encargada de atender las alarmas como la resolución DNS contra los servidores de Google. Adicionalmente a la derecha entontaremos información complementaria como Sistema operativo, tipo de nodo, MAC, IP, entre otras.Ahora bien, hasta aquí no deja de ser un comportamiento al uso, Ahora bien, ¿cómo se vería por ejemplo si quisiera ponerse online con la CPU de un PLC? En este caso he elegido SIEMENS STEP7?

Pues bien podríamos ver algo así:

Como podemos ver en este caso ya vemos protocolos COTP y S7 aparte de otras alertas como “NEW-FUNC-CODE” propias de esta conexión.

A partir de aquí ya habrá que determinar la acción a tomar como puede ser si se trata de un falto positivo, intervención sin notificación previa a responsables, registro, tratamiento, etc. Tan importante es detectar las anomalías como saber qué hacemos con ellas, por lo que deberá existir un procedimiento de actuación y escalado para determinar qué hacer.

Hasta aquí ejemplo de qué es lo que veríamos en caso de que un nuevo nodo aparezca en nuestra red.

¡Nos vemos en la próxima!

¡Un saludo!