CVE-2017-6720 Denial of service in Cisco Small Business Managed Switches

Medium 6.5 Published Updated

An authenticated remote attacker can cause a denial of service on Cisco Small Business Managed Switches by sending a malicious SSH message.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
Not needed
Fix
None listed

What is CVE-2017-6720?

CVE-2017-6720 is a medium-severity denial of service vulnerability in Cisco Small Business Managed Switches, published on 21 Sep 2017. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A vulnerability in the Secure Shell (SSH) subsystem of Cisco Small Business Managed Switches software could allow an authenticated, remote attacker to cause a reload of the affected switch, resulting in a denial of service (DoS) condition. The vulnerability is due to improper processing of SSH connections. An attacker could exploit this vulnerability by logging in to an affected switch via SSH and sending a malicious SSH message. This vulnerability affects the following Cisco products when SSH is enabled: Small Business 300 Series Managed Switches, Small Business 500 Series Stackable Managed Switches, 350 Series Managed Switches, 350X Series Stackable Managed Switches, 550X Series Stackable Managed Switches, ESW2 Series Advanced Switches. Cisco Bug IDs: CSCvb48377.

Weakness: CWE-119

Which versions are affected by CVE-2017-6720?

It affects 85 products.

Products include Cisco Esw2-350g-52 Firmware, Cisco Esw2-350g-52dc Firmware, Cisco Esw2-550x-48 Firmware, Cisco Esw2-550x-48dc Firmware, Cisco Sf300-08 Firmware, Cisco Sf300-24 Firmware and 79 more.

How do I fix CVE-2017-6720?

No fix has been published for CVE-2017-6720 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2017-6720 being exploited?

There is no known exploitation of CVE-2017-6720 in the wild and no public exploit code.

Sources

Also known as GHSA-vgpr-hxgc-qpwh.

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