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AUSCERT External Security Bulletin Redistribution
Cisco ASA VPN Denial of Service Vulnerability
23 October 2013
AusCERT Security Bulletin Summary
Product: Cisco Adaptive Security Appliance
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2013-5544
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Cisco Security Notice
Cisco ASA VPN Denial of Service Vulnerability
CVE ID: CVE-2013-5544
Release Date: 2013 October 21 21:39 UTC (GMT)
Last Updated: 2013 October 22 15:18 UTC (GMT)
A vulnerability in the VPN authentication code that handles parsing of the
username from the certificate on the Cisco ASA firewall could allow an
unauthenticated, remote attacker to cause a reload of the affected device.
The vulnerability is due to parallel processing of a large number of Internet
Key Exchange (IKE) requests for which username-from-cert is configured. An
attacker could exploit this vulnerability by sending a large number of IKE
requests when the affected device is configured with the username-from-cert
command. An exploit could allow the attacker to cause a reload of the affected
device, leading to a denial of service (DoS) condition.
Product More Information CVSS
Cisco Adaptive Security CSCua91108 5.4/4.5
Appliance (ASA) Software
What Is a Cisco Security Notice?
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Security Notices to inform customers of low- to mid-level severity security
issues involving Cisco products.
Customers who wish to upgrade to a software version that includes fixes for
these issues should contact their normal support channels. Free software
updates will not be provided for issues that are disclosed through a Cisco
For additional information about Cisco PSIRT publications, see the Cisco
Security Vulnerability Policy at
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organizations to ensure that any applied workaround or fix is the most
appropriate in the intended network before it is deployed.
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