Vulnerability identifier: #VU51770

Vulnerability risk: Medium

CVSSv3.1: 5.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-1377

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco IOS
Operating systems & Components / Operating system
Cisco IOS XE
Operating systems & Components / Operating system
Cisco 1100 Series Industrial Integrated Services Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9400 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9500 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9300 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco 1000 Series Integrated Services Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco 4000 Series Integrated Services Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 3650 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 3850 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Cloud Services Router 1000V Series
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco ASR 1000 Series Aggregation Services Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco 2600 Series Multiservice Platforms
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9200 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9600 Series Switches
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Catalyst 9800 Series Wireless Controllers
Hardware solutions / Routers & switches, VoIP, GSM, etc

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to Address Resolution Protocol (ARP) entries are mismanaged. A remote attacker can pass specially crafted data to the application and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco IOS: 15.5.1.0.1 SY5

Cisco IOS XE: 15.5.1.0.1 SY5

Cisco 1100 Series Industrial Integrated Services Routers: All versions

Cisco Catalyst 9400 Series Switches: All versions

Cisco Catalyst 9500 Series Switches: All versions

Cisco Catalyst 9300 Series Switches: All versions

Cisco 1000 Series Integrated Services Routers: All versions

Cisco 4000 Series Integrated Services Routers: All versions

Cisco Catalyst 3650 Series Switches: All versions

Cisco Catalyst 3850 Series Switches: All versions

Cisco Cloud Services Router 1000V Series: All versions

Cisco ASR 1000 Series Aggregation Services Routers: All versions

Cisco 2600 Series Multiservice Platforms: All versions

Cisco Catalyst 9200 Series Switches: All versions

Cisco Catalyst 9600 Series Switches: All versions

Cisco Catalyst 9800 Series Wireless Controllers: All versions

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-arp-mtfhBfjE

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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