Cisco IOS TCP ACK denial of service

cisco-ios-cve20135469-dos (86794) The risk level is classified as MediumMedium Risk

Description:

Cisco IOS is vulnerable to a denial of service, caused by the improper closing of an established TCP connection. By sending a specially-crafted sequence of TCP ACK and FIN packets, a remote attacker could exploit this vulnerability to trigger an ACK storm and consume all available CPU resources.

*CVSS:

Base Score: 4.3
  Access Vector: Network
  Access Complexity: Medium
  Authentication: None
  Confidentiality Impact: None
  Integrity Impact: None
  Availability Impact: Partial
 
Temporal Score: 3.2
  Exploitability: Unproven
  Remediation Level: Official-Fix
  Report Confidence: Confirmed

Consequences:

Denial of Service

Remedy:

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

References:

  • Cisco Security Notice: Cisco IOS Software TCP ACK Storm Vulnerability.
  • BID-62083: Cisco IOS CVE-2013-5469 Remote Denial of Service Vulnerability
  • CVE-2013-5469: The TCP implementation in Cisco IOS does not properly implement the transitions from the ESTABLISHED state to the CLOSED state, which allows remote attackers to cause a denial of service (flood of ACK packets) via a crafted series of ACK and FIN packets, aka Bug ID CSCtz14399.
  • OSVDB ID: 96764: Cisco IOS Crafted Packet Sequence Handling ACK Storm Remote DoS
  • SA54710: Cisco IOS ACK Storm Denial of Service Vulnerability

Platforms Affected:

  • Cisco IOS

Reported:

Aug 30, 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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