Vulnerabilities / Threats

9/20/2017
05:55 PM
Connect Directly
Twitter
LinkedIn
Google+
RSS
E-Mail
50%
50%

Cisco SMI Still Exposing Network Switches Online

The high number of exposed and vulnerable devices online has remained largely unchanged since researchers began exploring SMI in 2010.

Cisco's Smart Install (SMI) protocol is leaving network switches exposed on the public Internet at a rate that has remained largely unchanged since researchers began digging for SMI flaws when it was first released in 2010, a new study shows.

SMI provides configuration and image management for Cisco switches and uses a combination of DHCP, TFTP, and a proprietary TCP protocol to help businesses deploy and run them.

Researchers at Rapid7 recently reassessed the public Internet for SMI exposure. Their goal was to highlight changes since the initial publication of SMI research and learn more about why SMI was being exposed insecurely.

Since its debut, several SMI flaws have been discovered and disclosed including CVE-2011-3271, which led to remote code execution, and denial of service issues CVE-2012-0385, CVE-2013-1146, CVE-2016-1349, and CVE-2016-6385.

In 2016, researchers have found a number of new SMI security issues. Experts from Tenable, Trustwave SpiderLabs, and Digital Security presented at the 2016 Zeronights security conference to disclose several problems with SMI that left the entire switch open for compromise if a user left SMI exposed and unpatched, neglecting Cisco's recommendations for securing it.

Each SMI-related security advisory published by Cisco has recommended disabling SMI unless it's needed. The company has offered coverage for SMI abuse, updated the documentation to secure SMI, and released a scanning tool so customers can know if they're affected by SMI problems. It also released SMI-related hardening fixes.

In its new July 2017 reassessment of the public Internet, Rapid7 used a method similar to Zeronights. The Rapid7 Labs' Sonar scan found a 13% decrease in the number of exposed SMI endpoints compared with the Zeronights research. Countries with a large number of IPv4 IPs and large network infrastructure are the most exposed. The United States was highest with 56,605 nodes exposed, or 26.3% of the total.

"The issue with exposing SMI is that it gives an attacker complete control over the configuration of the target switch," says Jon Hart, senior security researcher at Rapid7. At the minimum, he explains, there is the possibility of information disclosure, which is likely to include authentication data like usernames, passwords/hashes, firewall/ACL rules, and more.

On the more extreme end, he continues, SMI exposure could let an attacker completely compromise the target switch and load arbitrary switch operating system code. They could execute code of their choosing and modify, redirect, or intercept switch transit traffic.

"Compromising a switch puts an attacker in a very advantageous position offensively," says Hart. "Being closer network-wise to additional target devices that connect to or through the compromised switch affords an attacker the ability to perform attacks against these additional targets."

Businesses can protect themselves by updating to newer versions of the relevant code powering these switches, which will likely remove any current risk of being compromised via SMI, he says. It's an improvement from several years ago, when organizations could have been running and exposing SMI without knowing it.

Related Content:

Join Dark Reading LIVE for two days of practical cyber defense discussions. Learn from the industry’s most knowledgeable IT security experts. Check out the INsecurity agenda here.

Kelly Sheridan is Associate Editor at Dark Reading. She started her career in business tech journalism at Insurance & Technology and most recently reported for InformationWeek, where she covered Microsoft and business IT. Sheridan earned her BA at Villanova University. View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Printers: The Weak Link in Enterprise Security
Kelly Sheridan, Associate Editor, Dark Reading,  10/16/2017
20 Questions to Ask Yourself before Giving a Security Conference Talk
Joshua Goldfarb, Co-founder & Chief Product Officer, IDDRA,  10/16/2017
Why Security Leaders Can't Afford to Be Just 'Left-Brained'
Bill Bradley, SVP, Cyber Engineering and Technical Services, CenturyLink,  10/17/2017
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: This comment is waiting for review by our moderators.
Current Issue
Security Vulnerabilities: The Next Wave
Just when you thought it was safe, researchers have unveiled a new round of IT security flaws. Is your enterprise ready?
Flash Poll
The State of Ransomware
The State of Ransomware
Ransomware has become one of the most prevalent new cybersecurity threats faced by today's enterprises. This new report from Dark Reading includes feedback from IT and IT security professionals about their organization's ransomware experiences, defense plans, and malware challenges. Find out what they had to say!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2017-0290
Published: 2017-05-09
NScript in mpengine in Microsoft Malware Protection Engine with Engine Version before 1.1.13704.0, as used in Windows Defender and other products, allows remote attackers to execute arbitrary code or cause a denial of service (type confusion and application crash) via crafted JavaScript code within ...

CVE-2016-10369
Published: 2017-05-08
unixsocket.c in lxterminal through 0.3.0 insecurely uses /tmp for a socket file, allowing a local user to cause a denial of service (preventing terminal launch), or possibly have other impact (bypassing terminal access control).

CVE-2016-8202
Published: 2017-05-08
A privilege escalation vulnerability in Brocade Fibre Channel SAN products running Brocade Fabric OS (FOS) releases earlier than v7.4.1d and v8.0.1b could allow an authenticated attacker to elevate the privileges of user accounts accessing the system via command line interface. With affected version...

CVE-2016-8209
Published: 2017-05-08
Improper checks for unusual or exceptional conditions in Brocade NetIron 05.8.00 and later releases up to and including 06.1.00, when the Management Module is continuously scanned on port 22, may allow attackers to cause a denial of service (crash and reload) of the management module.

CVE-2017-0890
Published: 2017-05-08
Nextcloud Server before 11.0.3 is vulnerable to an inadequate escaping leading to a XSS vulnerability in the search module. To be exploitable a user has to write or paste malicious content into the search dialogue.