Cisco NX-OS Bash access control

Summaryinfo

A vulnerability was found in Cisco NX-OS. It has been classified as critical. Affected by this vulnerability is an unknown functionality of the component Bash. This manipulation causes access control. This vulnerability is registered as CVE-2019-1593. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability has been found in Cisco NX-OS (Router Operating System) (unknown version) and classified as critical. Affected by this vulnerability is an unknown code block of the component Bash. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A vulnerability in the Bash shell implementation for Cisco NX-OS Software could allow an authenticated, local attacker to escalate their privilege level by executing commands authorized to other user roles. The attacker must authenticate with valid user credentials. The vulnerability is due to the incorrect implementation of a Bash shell command that allows role-based access control (RBAC) to be bypassed. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the Bash prompt. A successful exploit could allow the attacker to escalate their privilege level by executing commands that should be restricted to other roles. For example, a dev-ops user could escalate their privilege level to admin with a successful exploit of this vulnerability.

The bug was discovered 03/06/2019. The weakness was published 03/06/2019 as cisco-sa-20190306-nx-os-bash-e as confirmed advisory (Website). It is possible to read the advisory at tools.cisco.com. This vulnerability is known as CVE-2019-1593 since 12/06/2018. Attacking locally is a requirement. The requirement for exploitation is a single authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/29/2023). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

The commercial vulnerability scanner Qualys is able to test this issue with plugin 316423 (Cisco NX-OS Software Bash Shell Role-Based Access Control Bypass Privilege Escalation Vulnerability(cisco-sa-20190306-nx-os-bash-escal)).

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

Similar entries are available at VDB-131397, VDB-131396, VDB-131394 and VDB-131393. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• NX-OS

License

• commercial

Website

• Vendor: https://www.cisco.com/

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CPE 2.2info

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