Denial of service in Cisco IOS XE Software Web UI

Published: 2021-03-25

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-1220 CVE-2021-1356
CWE-ID	CWE-400
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Cisco 2600 Series Multiservice Platforms Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco ASR 1000 Series Aggregation Services Routers Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco 1000 Series Integrated Services Routers Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco Catalyst 9300 Series Switches Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco Catalyst 9500 Series Switches Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco Catalyst 9200 Series Switches Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco Catalyst 9800 Series Wireless Controllers Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco IOS XE Operating systems & Components / Operating system Cisco Wireless LAN Controller Hardware solutions / Firmware
Vendor	Cisco Systems, Inc

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Resource exhaustion

EUVDB-ID: #VU51725

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-1220

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of user-supplied input within the web UI of Cisco IOS XE Software. A remote authenticated user can send specially crafted HTTP request to the web UI and cause the web management software to hang and consume all available vty lines, preventing new session establishment.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Cisco 2600 Series Multiservice Platforms: All versions

Cisco ASR 1000 Series Aggregation Services Routers: All versions

Cisco 1000 Series Integrated Services Routers: All versions

Cisco Catalyst 9300 Series Switches: All versions

Cisco Catalyst 9500 Series Switches: All versions

Cisco Catalyst 9200 Series Switches: All versions

Cisco IOS XE: 17.2

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-webui-dos-z9yqYQAn
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvu99729

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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

2) Resource exhaustion

EUVDB-ID: #VU51726