Cisco IOS XE VTY Authentication security bypass

cisco-iosxe-cve20136979-sec-bypass (89901) The risk level is classified as MediumMedium Risk

Description:

Cisco IOS XE could allow a remote attacker to bypass security restrictions, caused by incomplete validations of the Linux-IOS Internal Network interface in VTY Authentication. If the source address is located in the 192.168.x.2 subnets and IP communication is available, an attacker could exploit this vulnerability to gain access to the device with the privilege level as configured against the VTY line, without being prompted for authentication.

*CVSS:

Base Score: 5.4
  Access Vector: Network
  Access Complexity: High
  Authentication: None
  Confidentiality Impact: Complete
  Integrity Impact: None
  Availability Impact: None
 
Temporal Score: 4
  Exploitability: Unproven
  Remediation Level: Official-Fix
  Report Confidence: Confirmed

Consequences:

Bypass Security

Remedy:

Refer to Cisco Security Notice for patch, upgrade or suggested workaround information. See References.

References:

  • Cisco Security Notice: Cisco IOS XE Software Telnet Authentication Bypass Vulnerability.
  • BID-64502: Cisco IOS XE Software Telnet Remote Authentication Bypass Vulnerability
  • CVE-2013-6979: The VTY authentication implementation in Cisco IOS XE 03.02.xxSE and 03.03.xxSE incorrectly relies on the Linux-IOS internal-network configuration, which allows remote attackers to bypass authentication by leveraging access to a 192.168.x.2 source IP address, aka Bug ID CSCuj90227.
  • OSVDB ID: 101351: Cisco IOS XE VTY Authentication Implementation Specific Source IP Authentication Bypass

Platforms Affected:

Reported:

Dec 23, 2013

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The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.

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