Vulnerability identifier: #VU20491

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1965

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco NX-OS
Operating systems & Components / Operating system

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to cause unexpected system behaviors and crashes.

The vulnerability exists in the Virtual Shell (VSH) session management due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. A remote authenticated attacker can repeatedly perform a remote management connection to the device and terminate the connection in an unexpected manner and cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition.

This vulnerability affects the following products that are running a Cisco NX-OS Software:

• MDS 9000 Series Multilayer Switches
• Nexus 3000 Series Switches
• Nexus 3500 Platform Switches
• Nexus 3600 Platform Switches
• Nexus 5500 Platform Switches
• Nexus 5600 Platform Switches
• Nexus 6000 Series Switches
• Nexus 7000 Series Switches
• Nexus 7700 Series Switches
• Nexus 9000 Series Switches in standalone NX-OS mode
• Nexus 9500 R-Series Switching Platform
• UCS 6200 Series Fabric Interconnects
• UCS 6300 Series Fabric Interconnects

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco NX-OS: 3.2 - 8.3

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nxos-memleak-dos

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.