Cisco IOS XE MACsec Key Agreement access control

Summaryinfo

A vulnerability was found in Cisco IOS XE and classified as critical. Affected by this issue is some unknown functionality of the component MACsec Key Agreement. The manipulation results in access control. This vulnerability is cataloged as CVE-2018-15372. The attack must originate from the local network. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Cisco IOS XE (Router Operating System) (the affected version is unknown). Affected is an unknown code of the component MACsec Key Agreement. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A vulnerability in the MACsec Key Agreement (MKA) using Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) functionality of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to bypass authentication and pass traffic through a Layer 3 interface of an affected device. The vulnerability is due to a logic error in the affected software. An attacker could exploit this vulnerability by connecting to and passing traffic through a Layer 3 interface of an affected device, if the interface is configured for MACsec MKA using EAP-TLS and is running in access-session closed mode. A successful exploit could allow the attacker to bypass 802.1x network access controls and gain access to the network.

The bug was discovered 09/26/2018. The weakness was shared 10/05/2018 with Cisco as cisco-sa-20180926-macsec as confirmed advisory (Website). The advisory is shared for download at tools.cisco.com. This vulnerability is traded as CVE-2018-15372 since 08/17/2018. The attack needs to be initiated within the local network. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1068.

The vulnerability was handled as a non-public zero-day exploit for at least 9 days. During that time the estimated underground price was around $5k-$25k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 316335 (Cisco IOS XE Software MACsec MKA Using EAP-TLS Authentication Bypass Vulnerability(cisco-sa-20180926-macsec)).

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at SecurityFocus (BID 105416†). The entries VDB-124886, VDB-124883 and VDB-124880 are related to this item. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS XE

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Once again VulDB remains the best source for vulnerability data.

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