Talos experts disclosed unpatched DoS flaws in Allen-Bradley adapter

Cisco Talos found several remotely exploitable denial-of-service (DoS) vulnerabilities in a Rockwell Automation industrial automation product.

A researcher from Cisco Talos released technical details of several remotely exploitable denial-of-service (DoS) vulnerabilities in an industrial automation product made by Rockwell Automation.

The product affected by the flaw is the Allen-Bradley 1794-AENT Flex I/O series B adapter, the issue resides in the Ethernet/IP request path port/data/logical segment functionality.

Cisco Talos researcher has found five high-severity buffer overflow vulnerabilities that impact Allen-Bradley devices running versions 4.003 and earlier.

“The Allen-Bradley Flex input/output system contains multiple denial-of-service vulnerabilities in its ENIP request path data segment. These bugs exist specifically in the 1794-AENT FLEX I/O modular platform. It provides many I/O operations and servers as a smaller physical device compared to other similar hardware.” reads the Cisco Advisory.

An attacker could exploit the above vulnerabilities by sending a specially crafted, malicious packet to the vulnerable device, this will causing a loss of communication between the victim’s network and the device resulting in denial-of-service. 

Talos reported the flaws to Rockwell Automation in February and for two times the vendor requested disclosure extensions. When Rockwell Automation requested a third extension, Talos decided to disclose the issues on October 12 regardless of whether or not the vendor has released security updates.

Rockwell Automation published a security advisory for its registered customers on October 12 that includes general recommendations to prevent attacks exploiting the above flaws.

The vendor recommends configuring the devices to accept CIP connections only from trusted sources on port 44818. The company also suggests implementing network segmentation and security controls to minimize exposure of affected devices. Other recommendations include the use of firewalls, VPNs and other network infrastructure controls.

Pierluigi Paganini

(SecurityAffairs – hacking, Allen-Bradley)