sb-au logo
Story image

Claroty reveals DoS vulnerability in Siemens protocol

20 Feb 2020

Claroty has today announced its discovery of a vulnerability in the Siemens Digsi 4 protocol. 

The threat allows for a denial-of-service (DoS) attack against Siemens SIPROTEC 4 protection relays, designed specifically for electrical substations. 

The vulnerability was discovered by Claroty researcher Tal Keren.

The security breach represents the same protocol that was exploited by the Industroyer malware, also referred to as Crashoverride, which was used to attack a Ukrainian power grid in 2016.   

Claroty immediately reported this research and coordinated with Siemens, which has now released an advisory with workarounds and mitigations.

It contained targeted industrial cybersecurity (ICS) payloads that allowed it to communicate using ICS protocols and specifically attack the electrical substations of the targeted companies. 

An important component in a substation is the protection relay, which is responsible for monitoring the actual current transmitted in every location and may trip any circuit breaker if anything unexpected happens. 

Without this protection relay, anything from a power outage to physical damage and even safety issues could occur.

Some of the payloads used by Industroyer were designed to cause DoS on the protection relays and remote terminal units (RTU) used in the targeted power grid companies and act as a kill switch. 

One of the specifically targeted ICS payloads found in the Industroyer malware that was implemented caused DoS on Siemens SIPROTEC 4 protection relays. 

This vulnerability used the SIPROTEC 4 programming protocol (Digsi 4) that communicates over UDP port 50000, and the proof of concept (POC) code implementing it is available publicly.  

The newest vulnerability discovered by Claroty uses a malicious packet in that same protocol to cause a DoS on those relays, thus allowing an attacker to reproduce the damage caused by Industroyer. 

This Digsi4 protocol allows users to program the protection relay and change its behaviour.

This protocol was developed by Siemens as a proprietary protocol.

The challenge for traditional IT security products aiming to protect against such attacks is exacerbated, as a specific understanding of the protocol and deep packet inspection (DPI) capabilities are required. 

The advisory published by Siemens contains workarounds and mitigations for this issue. 

Siemens has also improved security in the newer SIPROTEC 5 relays, whose communication protocol is encrypted and utilises improved security. 

Many other protection relays and other types of ICS hardware in the industry use proprietary protocols for programming purposes.

Securing these critical devices requires a deep understanding of those protocols, a fundamental knowledge of Operational Technology (OT) security, and continuous research to find and map potential vulnerabilities—whether in the design of the protocol, implementation, or determining attempts to abuse it.

Link image
How to better protect your organisation's most valuable asset - its data.
Data resilience strategies are becoming increasingly critical in relation to the skyrocketing value of data and the proliferation of malicious entities wishing to steal it.More
Story image
ESET launches the latest version of its Mobile Security solution
“With this latest version of ESET Mobile Security, we want to ensure our users feel completely secure when performing financial transactions on their devices, in addition to being protected from malware and phishing attempts."More
Story image
Acronis announces new security endpoint solution
The solution is an integration of data protection and cybersecurity which provides customers with effective endpoint protection in a landscape where the pointlessness of perimeter security is becoming more pronounced.More
Link image
What's new in Genetec Security Center 5.9
The platform supports physical security that empowers organisations with greater situational awareness.More
Story image
Check Point acquires Odo Security to bolster remote security offering
The deal will integrate Odo’s remote access software with Check Point’s Inifinity architecture, bolstering the latter company’s remote security capabilities in a time where working and learning from home has become the norm, and looks to largely remain that way in the near future.More
Story image
Emotet malware is on a rampage after months of silence
CERT agencies around the world are reporting a surge in cyber attacks related to the Emotet malware, which is being distributed by email.More