Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Network Security

08:05 AM
Larry Loeb
Larry Loeb
Larry Loeb

Cisco Warns of Possible Smart Install Client Hacking

Following an alert by US-CERT about possible hacking by foreign governments, Cisco is warning customers about a port vulnerability in the company's legacy Smart Install Client.

In March, the US Computer Emergency Readiness Team (US-CERT) issued an unprecedented alert about Russian hacking of industrial control systems, especially in the energy sector.

Done in conjunction with the US Department of Homeland Security and the FBI, the CERT alert did not specify exactly how this was all happening. However, the details are now seeping out. (See FBI & DHS Accuse Russia of Hacking Critical Infrastructure.)

Cisco Talos has found evidence of attempts to attack Cisco switches that are used in infrastructure installations that fit the profile CERT warned about. Groups such as Dragonfly, Crouching Yeti and Energetic Bear are linked to the attacks, with Dragonfly seemingly the main perpetrator.

The attacks are focused on the Cisco Smart Install (SMI) Client, legacy utility. When it was originally released -- in a time that had differing threat models and IT didn't consider someone hacking the switch – the client allowed for the no-touch installation of Cisco switches. It has since been superseded by the Cisco Network Plug and Play solution.

But when end-users install the switch with the new method, they did not configure or disable the obsolete Smart Install protocol. So, the client will still be listening in the background for the "installation/configuration" commands that it expects.

In its report, Cisco noted that the protocol: "can be abused to modify the TFTP server setting, exfiltrate configuration files via TFTP, modify the configuration file, replace the IOS image, and set up accounts, allowing for the execution of IOS commands."

In February 2017, Cisco first issued an advisory about misuse of the protocol. It's not a new issue.

What is new, however, is the increase in Shodan scans for port 4786 -- the port used in exploiting SMI -- which has occurred since the company first issued an advisory. Cisco reports that there are 168,000 SMI-enabled Cisco switches left exposed, which is less than the 251,000 that were observed in 2016.

However, there are reports that a hacker group calling itself "JHT" used this exploit over this weekend to nail Russian and Iranian networks that were subject to the vulnerability. Reports indicated that 3,500 of the affected switches were in Iran. The attack affected Internet service providers and reportedly cut off web access for their subscribers.

This situation differs from the vulnerability that was recently found by Embedi in the Smart Install client. In that case, a specially crafted malicious message can cause a stack-based buffer overflow. Cisco has issued a patch for it, but it does not directly relate to the protocol misuse issue that Cisco is once again discussing.

The fundamentals of network security are being redefined -- don't get left in the dark by a DDoS attack! Join us in Austin from May 14-16 at the fifth-annual Big Communications Event. There's still time to register and communications service providers get in free!

There are a few mitigation paths here.

Cisco has released an open source tool to scan and check if the protocol is still present in switch installations. There is also a Snort path (SID: 41722-41725) to detect any attempts to leverage this type of technology.

Additionally Cisco advises removal of the Smart Install Client from all devices where it is not used. To remove the Smart Install, Cisco recommends running the no vstack command on the switch. If that isn't possible, then an access control list can be implemented to limit access to specified hosts.

Switches are building blocks of control systems, and can cause great damage if misused. It is refreshing to see Cisco emphasize solutions to what could be a dangerous problem.

Related posts:

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 8/10/2020
Pen Testers Who Got Arrested Doing Their Jobs Tell All
Kelly Jackson Higgins, Executive Editor at Dark Reading,  8/5/2020
Researcher Finds New Office Macro Attacks for MacOS
Curtis Franklin Jr., Senior Editor at Dark Reading,  8/7/2020
Register for Dark Reading Newsletters
White Papers
Cartoon Contest
Current Issue
Special Report: Computing's New Normal, a Dark Reading Perspective
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
The Changing Face of Threat Intelligence
The Changing Face of Threat Intelligence
This special report takes a look at how enterprises are using threat intelligence, as well as emerging best practices for integrating threat intel into security operations and incident response. Download it today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
PUBLISHED: 2020-08-11
A Cross-Site Request Forgery (CSRF) vulnerability was discovered in the System Management Interface Web component of Avaya Aura Communication Manager and Avaya Aura Messaging. This vulnerability could allow an unauthenticated remote attacker to perform Web administration actions with the privileged ...
PUBLISHED: 2020-08-11
An issue was discovered in certain configurations of GNOME gnome-shell through 3.36.4. When logging out of an account, the password box from the login dialog reappears with the password still visible. If the user had decided to have the password shown in cleartext at login time, it is then visible f...
PUBLISHED: 2020-08-11
django-celery-results through 1.2.1 stores task results in the database. Among the data it stores are the variables passed into the tasks. The variables may contain sensitive cleartext information that does not belong unencrypted in the database.
PUBLISHED: 2020-08-11
There is a possible out of bounds read due to an incorrect bounds check.Product: AndroidVersions: Android SoCAndroid ID: A-152225183
PUBLISHED: 2020-08-11
The Temi application 1.3.3 through 1.3.7931 for Android has hard-coded credentials.