ICS Alert (ICS-ALERT-17-209-01)

CAN Bus Standard Vulnerability

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NCCIC/ICS-CERT is aware of a public report of a vulnerability in the Controller Area Network (CAN) Bus standard with proof-of-concept (PoC) exploit code affecting CAN Bus, a broadcast based network standard. According to the public report, which was coordinated with ICS-CERT prior to its public release, researchers Andrea Palanca, Eric Evenchick, Federico Maggi, and Stefano Zanero identified a vulnerability exploiting a weakness in the CAN protocol that allows an attacker to perform a denial-of-service (DoS) attack.

ICS-CERT has notified some affected vendors, primarily auto manufacturers and entities within the healthcare industry, about the report to confirm the vulnerability and to identify mitigations. ICS-CERT is issuing this alert to provide notice of the report and identify baseline mitigations for reducing risks to these and other cybersecurity attacks.

The report included vulnerability details and PoC exploit code for the following vulnerability:


Vulnerability TypeRemotely ExploitableImpact
Resource ExhaustionAutomobile exploit; requires physical accessDenial of Service

CAN is widely used throughout the Critical Manufacturing, Healthcare and Public Health, and Transportation Systems sectors.

Successful exploitation of the vulnerability on an automobile may allow an attacker with physical access and extensive knowledge of CAN to reverse engineer network traffic to perform a DoS attack disrupting the availability of arbitrary functions of the targeted device.

The severity of the attack varies depending on how the CAN is implemented on a system and how easily an input port (typically OBD-II) can be accessed by a potential attacker. This attack differs from previously reported frame-based attacks, which are typically detected by IDS/IPS systems. The exploit focuses on recessive and dominant bits to cause malfunctions in CAN nodes rather than complete frames.

The CAN bus protocol is used widely by the automotive industry and other industries; however, the impact and exploitability of the identified vulnerability is dependent on the implementation and controls. 


The only current recommendation for protecting against this exploit is to limit access to input ports (specifically OBD-II) on automobiles. ICS-CERT is currently coordinating with vendors and security researchers to identify mitigations.

ICS-CERT also provides a control systems recommended practices page on the ICS-CERT web site. Several recommended practices are available for reading or download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Organizations that observe any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents. 

Contact Information

For any questions related to this report, please contact the CISA at:

Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  https://us-cert.cisa.gov/ics 
or incident reporting:  https://us-cert.cisa.gov/report

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