A vulnerability was found in Cisco IOS XR (Router Operating System) (affected version unknown). It has been classified as critical. Affected is an unknown functionality of the component SSH Authentication Handler. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A vulnerability in the Secure Shell (SSH) authentication function of Cisco IOS XR Software could allow an authenticated, remote attacker to successfully log in to an affected device using two distinct usernames. The vulnerability is due to a logic error that may occur when certain sequences of actions are processed during an SSH login event on the affected device. An attacker could exploit this vulnerability by initiating an SSH session to the device with a specific sequence that presents the two usernames. A successful exploit could result in logging data misrepresentation, user enumeration, or, in certain circumstances, a command authorization bypass. See the Details section for more information.

The weakness was disclosed 06/05/2019 as cisco-sa-20190605-iosxr-ssh as confirmed advisory (Website). The advisory is shared for download at tools.cisco.com. This vulnerability is traded as CVE-2019-1842 since 12/06/2018. It is possible to launch the attack remotely. The successful exploitation needs a authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/28/2023). The MITRE ATT&CK project declares the attack technique as T1548.002.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The entries VDB-11619, VDB-12837, VDB-13435 and VDB-171298 are pretty similar.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS XR

License

• commercial

CPE 2.3info

• 🔍

CPE 2.2info

• 🔍

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