As part of Team82's continued mission and focus to support and secure critical infrastructure, researcher Tal Keren has discovered a vulnerability (CVE-2019-19279) in the Siemens Digsi 4 protocol. This vulnerability allows for a denial-of-service (DOS) attack against Siemens SIPROTEC 4 protection relays, designed specifically for electrical substations. This is the same protocol that was exploited by the Industroyer malware in 2016.
Team82 immediately reported this research and coordinated with Siemens, which has now released an advisory (SSA-974843) with workarounds and mitigations.
The Industroyer malware, also referred to as Crashoverride, was used to attack the Ukraine power grid in 2016, and 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. Substations are critical in power generation, distribution, and transmission networks. A very 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 (CVE-2015-5374) 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 behavior. Like many other ICS related protocols, this protocol was developed by Siemens as a proprietary protocol. In that, the challenge for traditional IT security products aiming to protect against such attacks is increased, as a specific understanding of the protocol and deep packet inspection (DPI) capabilities are required.
It is important to note that 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 utilizes 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 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.
CWE-257: Storing Passwords in a Recoverable Format
RND encrypts passwords with a hardcoded weak secret key and returns the passwords in plaintext. If the server were compromised, an attacker could gain all the plaintext passwords and decrypt them.
No patches have been supplied by the vendor at this time. To mitigate risk, network administrators should limit access to the wireless management environments that use these affected products, allowing a limited set of trusted users and their authenticated clients to manage Ruckus infrastructure via a secure protocol such as HTTPS or SSH.
CVSS v3: 5.3
CWE-321: Use of Hard-coded Cryptographic Key
A built-in user called sshuser, with root privileges, exists on the RND platform. Both public and private ssh keys exist in the sshuser home directory. Anyone with the private key can access an RND server as sshuser.
No patches have been supplied by the vendor at this time. To mitigate risk, network administrators should limit access to the wireless management environments that use these affected products, allowing a limited set of trusted users and their authenticated clients to manage Ruckus infrastructure via a secure protocol such as HTTPS or SSH.
CVSS v3: 10.0
CWE-259: Use of Hard-coded Password
RND includes a jailed environment to allow users to configure devices without complete shell access to the underlying operating system. The jailed environment includes a built-in jailbreak for technicians to elevate privileges. The jailbreak requires a weak password that is hardcoded into the environment. Anyone with this password can access an RND server with root permissions.
No patches have been supplied by the vendor at this time. To mitigate risk, network administrators should limit access to the wireless management environments that use these affected products, allowing a limited set of trusted users and their authenticated clients to manage Ruckus infrastructure via a secure protocol such as HTTPS or SSH.
CVSS v3: 8.2
CWE-321: Use of Hard-coded Cryptographic Key
RND uses a secret key on the backend web server to ensure that session JWTs are valid. This secret key is hardcoded into the web server. Anyone with knowledge of the secret key could create a valid JWT, thus bypassing the typical authentication to access the server with administrator privileges.
No patches have been supplied by the vendor at this time. To mitigate risk, network administrators should limit access to the wireless management environments that use these affected products, allowing a limited set of trusted users and their authenticated clients to manage Ruckus infrastructure via a secure protocol such as HTTPS or SSH.
CVSS v3: 9.8
CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')
An authenticated vSZ user supplies an IP address as an argument to be run in an OS command, but this IP address is not sanitized. A user could supply other commands instead of an IP address to achieve RCE.
No patches have been supplied by the vendor at this time. To mitigate risk, network administrators should limit access to the wireless management environments that use these affected products, allowing a limited set of trusted users and their authenticated clients to manage Ruckus infrastructure via a secure protocol such as HTTPS or SSH.
CVSS v3: 9.0
