Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted device.
The vulnerability is due to improper handling of malformed packets. An unauthenticated, remote attacker could exploit this vulnerability by sending malicious network packets to the device. If successful, the attacker could cause the device to become unresponsive, resulting in a DoS condition.
Cisco confirmed the vulnerability in a security advisory and released updated software.
Indicators of Compromise
Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The Vendor Announcements section of this alert contains a link to the advisory.
The vulnerability is due to improper memory management on devices that are running Cisco IOS Software that is configured to use the Cisco IOS Intrusion Prevention System (IPS) or Cisco IOS Zone-Based Firewall feature. On such devices, the processing of large amounts of network traffic could cause a memory leak in the Chunk Manager process, possibly leading to an out-of-memory condition that could render the device unresponsive.
An unauthenticated, remote attacker could exploit this vulnerability by sending a series of malicious network packets to the device. The processing of the malicious packets could cause the device to fail to free memory resources, causing the device to become unresponsive.
Only devices that are configured for the Cisco IOS IPS or Cisco IOS Zone-Based Firewall feature are vulnerable to exploitation.
If exploits render devices unavailable, other end hosts and network devices that depend on the device may also lose network connectivity, which may affect a large number of systems beyond the vulnerable device.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected 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.