Team82 recently discovered three new Windows-based vulnerabilities in B&R Automation Studio, an integrated industrial automation software environment that supports a wide range of operational technology (OT) functions, including controls, human machine interfaces (HMIs), and safety. B&R Automation Studio is used globally, particularly among chemical, energy, and critical manufacturing companies.
The discovered vulnerabilities relate specifically to the product's update service, require a low level of skill to exploit, and can be leveraged through remote code execution. After being notified by Claroty, B&R Automation issued patches for these vulnerabilities, as well as a US-CERT advisory.
B&R Automation says it has not found evidence indicating any of the vulnerabilities discovered by Claroty have been used maliciously. That being said, Preminger and Anikster's findings provide an illustrative example of how an attacker can leverage software vulnerabilities to exploit computers used for engineering work within an OT environment.
The specific nature of the vulnerabilities uncovered by Claroty are as follows:
Improper privilege management (CVE-2019-19100): This privilege escalation vulnerability could allow authenticated users to delete arbitrary files via an exposed interface.
Missing required cryptographic step (CVE-2019-19101): This missing security communication definition, which leads to incomplete TLS encryption and validation, can enable unauthenticated users to perform man-in-the middle (MITM) attacks via the B&R upgrade server.
Path traversal (CVE-2019-19102): This directory traversal vulnerability in SharpZipLib, also known as a "zip slip," allows unauthenticated users to write to certain local directories.
According to Preminger, an attacker could combine the missing required cryptographic step with the path traversal vulnerability to intervene during a software update, conduct a MITM attack, and install their own malicious code within a victim's network. Leveraging these vulnerabilities, a threat actor could conduct a DNS cache poisoning attack against computers within an OT network while posing as the B&R update server to avoid detection.
In a DNS cache poisoning attack, also known as DNS spoofing, an adversary diverts traffic to a malicious destination while altering DNS records to create the impression of normal, legitimate activity. "This attack is based on hijacking a domain, which becomes much easier if the attacker has gained access to a closed ICS network," Preminger explained in a recent interview with SecurityWeek. "Often, there are no DNS servers to respond to the client. Windows will fallback to local discovery protocols, which are easier to deceive."
B&R Automation recommends applying product updates at the earliest convenience and has provided several workaround mitigations for users unable to upgrade immediately.
To learn more about how Claroty can help your team discover and mitigate vulnerabilities within your OT environment, request a demo.
CWE-191 INTEGER UNDERFLOW (WRAP OR WRAPAROUND):
The affected product is vulnerable to an integer underflow. An unauthenticated attacker could send a malformed HTTP Requesty, which could allow the attacker to crash the program.
Planet Technology recommends users upgrade to version 1.305b241111 or later.
CVSS v3: 5.3
CWE-78 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN OS COMMAND ('OS COMMAND INJECTION'):
The affected product is vulnerable to a command injection. An unauthenticated attacker could send commands through a malicious HTTP request which could result in remote code execution.
Planet Technology recommends users upgrade to version 1.305b241111 or later.
CVSS v3: 9.8
CWE-121 STACK-BASED BUFFER OVERFLOW:
The affected product is vulnerable to a stack-based buffer overflow. An unauthenticated attacker could send a malicious HTTP request that the webserver fails to properly check input size before copying data to the stack, potentially allowing remote code execution.
Planet Technology recommends users upgrade to version 1.305b241111 or later.
CVSS v3: 9.8
CWE-359 Exposure of Private Personal Information to an Unauthorized Actor:
Ruijie Reyee OS versions prior to 2.260.0.1329 contains a a feature that could enable sub accounts
or attackers attackers to view and exfiltrate sensitive information from all cloud accounts registered to Ruijie's services.
CVSS v3: 6.5
CWE-1391 Use of Weak Credentials:
Ruijie Reyee OS versions prior to 2.260.0.1329 uses weak credential mechanism that could allow
an attacker to easily calculate MQTT credentials.
Ruijie reports that the issues have been fixed on the cloud and no action is needed by end users.
CVSS v3: 7.5