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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.2458 Cisco IOS Software DHCPv6 Server Implementation Denial of Service Vulnerability 21 September 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS Software Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2015-6297 Original Bulletin: http://tools.cisco.com/security/center/viewAlert.x?alertId=41060 - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Alert Cisco IOS Software DHCPv6 Server Implementation Denial of Service Vulnerability Threat Type: CWE-399: Resource Management Errors IntelliShield ID: 41060 Version: 1 First Published: 2015 September 18 04:41 GMT Last Published: 2015 September 18 04:41 GMT Port: Not available CVE: CVE-2015-6297 Urgency: Unlikely Use Credibility: Confirmed Severity: Mild Damage CVSS Base: 5.0 CVSS Temporal: 4.1 Version Summary: Cisco IOS Software 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 DHCP version 6 (DHCPv6) server implementation of Cisco IOS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper handling of crafted DHCPv6 packets. An attacker could exploit this vulnerability by sending crafted DHCPv6 packets to be processed by the affected device. An exploit could allow the attacker to cause a reset of an affected process. Cisco has confirmed the vulnerability and released software updates. Warning Indicators At the time this alert was first published, Cisco 9000 Series Aggregation Services Router (ASR) version 5.2.0 (Base) devices running Cisco IOS Software were vulnerable. Other versions may also be affected. IntelliShield Analysis To exploit this vulnerability a remote attacker does not need to authenticate to pass the crafted DHCPv6 packets to the targeted device. This increases the likelihood of a possible exploit. 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 ID CSCun36525 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 reset, resulting in a DoS condition. Technical Information The vulnerability is due to improper handling of crafted DHCPv6 packets. An unauthenticated, remote attacker could exploit this vulnerability by sending crafted DHCPv6 packets to an affected device. A successful exploit could allow the attacker to cause a reset of the affected device, 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 can help protect affected systems from external attacks by using a solid firewall strategy. 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. 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 ASR 9000 Series Aggregation Services Routers 5.2.0(ED) Base Associated Products: N/A 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. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. 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On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBVf+P0X6ZAP0PgtI9AQJ1URAAtHui3TZfhJZ+SW1/Gc6rDRDnRieTl+N7 avRVKqQHFVwmFRxzMvZDlxQGFTbk1w167pRDUoxwtoM+nXvTyGPTuYbbs3l/Q1OO bIVSzNTC9AOiBLZjF+EhyZrRpw0eN+YEkXasDarDvJuyuXjS9X90wQaP2WWUuzdJ 3sB5a3pIFnIs7sPNBky8Y74VHZ5UvHTQwcwjaD3J6XTIq56HtEyL5zWBIFIZukl9 305SUFov6vXfQgUubJLTh69152JfYIkg1+2lgaGbsWk7fxdY+ho0sDh5u4oRizm8 jixUa0iXGlWzIe6qghhLr+cdU6Cf9g5Vx/rGhTANGoXD2aQKouC57k+Fp4+n+Oof ywWoKdWqVRI3mCPaJQfVUzgtsQln3HNMEXcAJK1nB9UmFMKw/8l3A1ZOSEO+LMN8 MvPhHXrJb42a498gi7ImdovFiXxuCy9BPEvDZ3z/l8zSdovDtqrI6p3ttJ/Z1zM8 XIcD9CcZsjLt/iySffFLWQmkVtuDDiVlQiw0A8edjwvRN8CMp64yFBJrZyBQLyg6 51SLYSwl7V9Y4xglBGg161lpYVnZ7YYsrmp7zD6LRLtw4l70DvWeqsDtlhmztNC2 1II8boM2kVPa22iYYZZrMSAr4H1OGqWeLVNFAfmp1TvdtviFsCxkjtYrs15Urka3 YDASE8ykKrk= =Aa7+ -----END PGP SIGNATURE-----