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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.1876 Cisco AsyncOS for Cisco Email Security Appliance Cluster Denial of Service Vulnerability 16 July 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco Email Security Appliance Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2015-4236 Original Bulletin: http://tools.cisco.com/security/center/viewAlert.x?alertId=39785 - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Alert Cisco AsyncOS for Cisco Email Security Appliance Cluster Denial of Service Vulnerability Threat Type: CWE-399: Resource Management Errors IntelliShield ID: 39785 Version: 1 First Published: 2015 July 10 15:40 GMT Last Published: 2015 July 10 15:40 GMT Port: Not available CVE: CVE-2015-4236 Urgency: Unlikely Use Credibility: Confirmed Severity: Mild Damage CVSS Base: 5.0 CVSS Temporal: 4.1 Version Summary: Cisco AsyncOS for Cisco Email Security Appliance contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available. Description A vulnerability in the clustering component of Cisco AsyncOS for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause the device to become unresponsive on the clustering and SSH configured ports. The vulnerability is due to improper handling of packets sent at a high rate when the system is configured for clustering. An attacker could exploit this vulnerability by sending packets to the targeted system at a high rate. An exploit could allow the attacker to cause the affected system to become unresponsive on the clustering and SSH configured ports, causing all new connections to these ports to fail. A reload is required to restore normal operational behavior. Cisco has confirmed the vulnerability and released software updates. Warning Indicators At the time this alert was first published, Cisco ESA releases 8.5.6-073, 8.5.6-074, and 9.0.0-461 were vulnerable. Later releases of Cisco ESA may also be vulnerable. IntelliShield Analysis To exploit this vulnerability, an attacker would need to send packets to the affected device at a high rate, making exploitation more difficult in environments that restrict access to untrusted sources. Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available. Vendor Announcements Cisco has released bug IDs CSCur13704 and CSCuq05636 for registered users, which contains additional details and an up-to-date list of affected product versions. Impact An unauthenticated, remote attacker could exploit this vulnerability to cause an affected device to become unresponsive on the clustering and SSH configured ports, resulting in a denial of service (DoS) condition. Technical Information The vulnerability is due to improper handling of packets sent at high rate to an affected system that is configured for clustering. An unauthenticated, remote attacker could exploit this vulnerability by sending packets to the target system at a high rate. An exploit could allow the attacker to cause the affected system to become unresponsive on the clustering and SSH configured ports, resulting in a DoS condition. Safeguards Administrators are advised to apply the appropriate updates. Administrators are advised to allow only trusted users to have network access. Administrators are advised to monitor affected systems. Patches/Software 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 email at tac@cisco.com. Alert History Initial Release Product Sets The security vulnerability applies to the following combinations of products. Primary Products: Cisco Cisco Email Security Appliance (ESA) 9.0 .0-461 | 8.5 .6-074, .6-073 Associated Products: N/A Alerts and bulletins on the Cisco Security Intelligence Operations Portal are highlighted by analysts in the Cisco Threat Operations Center and represent a subset of the comprehensive content that is available through Cisco Security IntelliShield Alert Manager Service. This customizable threat and vulnerability alert service provides security staff with access to timely, accurate, and credible information about threats and vulnerabilities that may affect their environment. LEGAL DISCLAIMER The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. 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