SB2021060213 - Authorization bypass in Cisco ASR 5000 Series Software



SB2021060213 - Authorization bypass in Cisco ASR 5000 Series Software

Published: June 2, 2021

Security Bulletin ID SB2021060213
Severity
Medium
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 secuirty vulnerabilities.


1) Improper Authorization (CVE-ID: CVE-2021-1539)

The vulnerability allows a remote user to gain unauthorized access to the system.

The vulnerability exists in the authorization process of Cisco ASR 5000 Series Software (StarOS) due to incorrect authorization of non-interactive CLI commands. A remote authenticate user can bypass TACACS authorization by sending a crafted Secure Shell (SSH) request to an affected device and execute a certain CLI commands.

Successful exploitation of the vulnerability may result in unauthorized access to sensitive information or denial of service condition.


2) Improper Authorization (CVE-ID: CVE-2021-1540)

The vulnerability allows a remote user to gain unauthorized access to the system.

The vulnerability exists due to incorrect authorization of non-interactive CLI commands in the authorization process of Cisco ASR 5000 Series Software (StarOS). A remote authenticated user can send a specially crafted SSH request to an affected device, bypass the nocli option and execute certain CLI commands.


Remediation

Install update from vendor's website.