Cisco Nexus 9000 Series Fabric Switches ACI Mode Border Leaf Endpoint Learning Vulnerability

A vulnerability within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances.

The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nexus-aci-dos

Security Impact Rating: Medium

CVE: CVE-2019-1977

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Upcoming Webinar: How to Detect Targeted Ransomware with MITRE ATT&CK

I do not need a solution (just sharing information)

Just raising awareness of an upcoming webinar on Aug 22, 2019:

How to Detect Targeted Ransomware with MITRE ATT&CK™
https://www.symantec.com/about/webcasts

Cyber criminals are turning to targeted ransomware at an accelerated pace, motivated no doubt by the success of recent attacks. Join experts from Symantec and MITRE as we explore the latest research and best practices for detecting targeted ransomware in your environment.

We will cover:
• The latest trends in attacks
• An in depth look at GoGalocker
• How to use the ATT&CK™ knowledge base to describe these threats
• Mitigations and defenses for dealing with Gogalocker

Ransomware, especially targeted variants like Ransom.Crysis and Ransom.Ryuk, remains a very real danger – do take measures to protect your organization!

Targeted Ransomware: Proliferating Menace Threatens Organizations
https://www.symantec.com/blogs/threat-intelligence/targeted-ransomware-threat  

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Policy Center change in 1.1.5.5 – PS Passwords Shareable

I do not need a solution (just sharing information)

Starting with 1.1.5.1 PolicyCenter by default does not allow you to push touch or look passwords to the PacketShapers due to security concerns. However, this is a problem as one cound guess. To change the behavior back to sharable you have to do the following (from support):

There is a security risk with enabling the password push feature, which is why it has been disabled.  The only way to re-enable it is on a case by case basis, as Symantec will require the serial number of the PolicyCenter.  Using this serial number, a request will be made to Engineering to create an enablement key, which will then be provided to Support.  Support will then provide the enablement key to the customer along with the following instructions:

  1. Access the PolicyCenter CLI.
  2. Enable debug mode: pc showdebug 1
  3. Enter the enablement key you were provided: pc enablepushpw <enablement key>
  4. Disable debug mode: pc showdebug 0

This PolicyCenter unit will now be able to centrally manage passwords for all PacketShapers that are registered to it. 

Rick

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