Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to errors in processing malformed Skinny Client Control Protocol (SCCP) network messages. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious request to the targeted device. Successful exploitation could allow the attacker to cause the device to reload, resulting in a DoS condition.
Cisco has 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 errors in processing malformed SCCP network messages. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious packet to a targeted device. The device will process the packet only if its origin IP address is registered by the device. When processed, the packet could cause the device to become unresponsive and reload, resulting in a DoS condition.
To exploit this vulnerability, an attacker must be able to send a malicious request originating from a registered IP address to a targeted device. If autoregistration is enabled, which is the default configuration, an attacker could register an IP address and use that address to send a malicious request. The attacker may require access to internal networks to send a request to a device.
If an exploit is successful, the attacker could cause a targeted device to stop responding and automatically reload, resulting in a DoS condition. The device would be unable to process network requests while it starts. Repeated attacks could cause the device to continue to reload, resulting in an extended DoS condition as long as the requests continue.
Administrators are advised to apply the available software 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 implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
Administrators are advised to monitor critical systems.
The Cisco Applied Intelligence team has created the following companion document to guide administrators in identifying and mitigating attempts to exploit this vulnerability prior to applying updated software: cisco-amb-20100324-voice
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.