Cisco’s Smart Install protocol is still being abused in attacks — five years after the networking giant issued its first warning — and there are still roughly 18,000 internet-exposed devices that could be targeted by hackers.
Cisco describes Smart Install as a plug-and-play configuration and image-management feature that provides zero-touch deployment for new switches. Smart Install can be very useful for organizations, but it can also pose a serious security risk.
Once a device has been set up through Smart Install, the feature remains enabled and it can be accessed without authentication. This has allowed malicious actors to remotely target devices on which Smart Install is enabled, including to reload devices, load a new operating system image, and execute arbitrary commands with elevated privileges.
Cisco first warned about the misuse of Smart Install in 2016, after an exploitation tool was made available. The company issued more warnings in 2017 and 2018 — in 2018 it identified hundreds of thousands of exposed devices, including in critical infrastructure organizations.
It was reported in 2018 that the Smart Install feature had been targeted by hacktivists in attacks aimed at Cisco switches in Iran and Russia as part of an apparent pro-US attack, as well as a state-sponsored cyberespionage group linked to Russia.
In 2016, the number of networking devices exposed to attacks via Smart Install exceeded 250,000, and dropped to 168,000 by 2018. The Shadowserver Foundation is still tracking the number of potentially vulnerable devices and it currently reports seeing nearly 18,000 that are exposed to the internet, many in North America, South Korea, the UK, India and Russia.
The Black Lotus Labs cybersecurity unit at IT solutions provider Lumen Technologies noticed last month that a hacktivist group hacked at least 100 internet-exposed routers housed by both public and private sector organizations, a majority located in the United States.
The attackers abused the Cisco Smart Install protocol to replace existing configuration files with a text file containing an anti-West manifesto. This caused impacted devices to stop routing traffic.
“By abusing this protocol, the threat actor instructed the exposed router to use TFTP, a common transfer method for router configuration files, to pull down a text file containing a manifesto, stored at the URL: tftp://18.104.22.168.vultr[.]com/my.conf. This installation replaced the existing router configuration, preventing the devices from routing traffic,” Black Lotus Labs researchers explained.
Since the beginning of 2021, they claim to have seen more than 800 unique scanners looking for a port associated with the Smart Install feature.
“Despite the long history of advanced threat actors and hacktivists abusing the Smart Install protocol, the ongoing exposure of devices continues to be of interest to actors seeking to exploit it,” the researchers said.