Cisco ISM module for ISR G2 contains a vulnerability that could allow an authenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in authentication header packets processing on the Cisco ISM module for ISR G2 could allow an authenticated, remote attacker to cause a reload of the affected module.
The vulnerability is due to improper processing of malformed authentication header packets. An attacker could exploit this vulnerability by sending a stream of malformed authentication header packets over an established IPsec security association. An exploit could allow the attacker to cause a reload of the affected module, resulting in a denial of service (DoS) condition for IPsec traffic.
Cisco has confirmed the vulnerability in a security notice and software updates are available.
At the time this alert was first published, Cisco IOS Software Releases 15.3(200)T and prior were vulnerable. Later releases of Cisco IOS Software may also be affected.
To exploit this vulnerability, the attacker must authenticate to a targeted system to send malformed authentication header packets. This access requirement limits the possibility of a successful exploit.
Customers are advised to review the bug reports in the "Vendor Announcements" section for a current list of affected versions.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
An authenticated, remote attacker could exploit this vulnerability to cause the ISM module on an affected device to reload, resulting in a DoS condition.
The vulnerability is due to improper processing of malformed authentication header packets by the Cisco ISM module for ISR G2 devices running on an affected software release.
An authenticated, remote attacker could exploit this vulnerability by sending a stream of malformed authentication header packets over an established IPsec security association. If successful, the attacker could cause the affected module to reload, resulting in a DoS condition.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only privileged users to access administration or management systems.
Restrict privileged management access to devices to prevent information disclosure and unauthorized access. Ensure security features such as Management Plane or Control Plane Protection are applied to a device. For best practices for securing interactive management sessions, consult Cisco Guide to Harden Cisco IOS Devices.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at firstname.lastname@example.org for assistance.
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