Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper processing of DNS packets in certain device configurations. An unauthenticated, remote attacker could exploit the vulnerability by sending DNS packets through a device with a vulnerable configuration. If successful, the attacker could cause the device to reload, resulting in a DoS condition.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Cisco has published a list of affected Cisco IOS Software releases in a security advisory. The Vendor Announcements section of this alert contains a link to the security advisory.
The vulnerability is due to improper processing of DNS packets on devices with a specific configuration running Cisco IOS with the Intrusion Prevention Feature (IPS) enabled.
An unauthenticated, remote attacker could exploit the vulnerability by sending DNS packets through a device with a vulnerable Cisco IOS IPS configuration. Processing the DNS packets could cause the device to reload, resulting in a DoS condition.
Only devices with certain specific configurations are affected by this vulnerability, decreasing the likelihood of a successful exploit.
Administrators are advised to apply the appropriate updates.
Administrators may consider disabling DNS inspection on vulnerable systems.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at firstname.lastname@example.org.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.