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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.2374 Cisco Web Security Appliance Malformed HTTP Response Denial of Service Vulnerability 10 September 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco Web Security Appliance Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote with User Interaction Resolution: Mitigation CVE Names: CVE-2015-6290 Original Bulletin: http://tools.cisco.com/security/center/viewAlert.x?alertId=40896 - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Alert Cisco Web Security Appliance Malformed HTTP Response Denial of Service Vulnerability Threat Type: CWE-119: Buffer Errors IntelliShield ID: 40896 Version: 1 First Published: 2015 September 09 20:07 GMT Last Published: 2015 September 09 20:07 GMT Port: Not available CVE: CVE-2015-6290 Urgency: Unlikely Use Credibility: Confirmed Severity: Mild Damage CVSS Base: 4.3 CVSS Temporal: 3.7 Version Summary: Cisco Web Security Appliance contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are not available. Description A vulnerability in the web interface of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a partial denial of service (DoS) condition due to memory management failures during processing of TCP connections. The vulnerability is due to the improper handling of a malformed HTTP server responses. An unauthenticated, remote attacker with a privileged network position could exploit the vulnerability by conducting a man-in-the-middle (MitM) attack and supplying malformed HTTP server responses to the vulnerable device. A successful exploit could allow the attacker to cause the device to improperly close TCP connections and fail to free memory resources, resulting in a partial DoS condition. Cisco has confirmed the vulnerability; however, software updates are not available. Warning Indicators At the time this alert was first published, Cisco Web Security Appliance version 8.0.7 was affected. Later versions of Cisco WSA may also be affected. IntelliShield Analysis To exploit the vulnerability, the attacker would need to send crafted HTTP requests to the targeted system through the WSA web interface. Because the attacker does not need to authenticate to send the crafted HTTP requests, the likelihood of an exploit is increased. Vendor Announcements Cisco has released bug ID CSCuw10426 for registered users that contains additional details and an up-to-date list of affected product versions. Impact An unauthenticated, remote attacker could exploit this vulnerability to cause a DoS condition on the targeted device. Technical Information The vulnerability is due to improper handling of malformed HTTP server responses. An attacker could exploit this vulnerability by causing the vulnerable application to process a malformed HTTP server response. A successful exploit could allow the attacker to cause a DoS condition on the targeted device due to improperly freed memory resources. Safeguards 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 physical security for production servers. Administrators are advised to contact the vendor regarding future updates and releases. Patches/Software Updates are not available. Alert History Initial Release Product Sets The security vulnerability applies to the following combinations of products. Primary Products: Cisco Cisco Web Security Appliance (WSA) 8.0 Base, .5, .5 Hot Patch 1, .6, .7 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. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBVfDOBH6ZAP0PgtI9AQI3kg/+M6MHj2h62A3h8PEnbHgnKsCWcNJCE2Pz J+UxD2cp6xY9aXj/8umI7Nq2nweZMA3pSQuC6VoJn8twv2X11hDIkSvdbJtl78KY Yz2JTI7AO6GS8oulS2yfQxx50tjs75DdGke/3R/psKJIXgNM5YrEingqW1dcrZbb aa9ujKXJePRKoZA8MjaHdbQ0m/cJDQYN+k9Q65OKWLPuVjl7jFkexrHYKfh8lmf/ RoMQ5UpvrkZMbhOQ8ki3+hZNZGEjJ8UDoU3Yy8wP9Cuy59obPk304OFUYjHPmts1 6K3+epoSW8Gu2goWrYMzjEURKlTtwTrJEyseewqFyy4uvgePI3vm8e8Sqvjah3ik Qe3fmVP6OKsCdwaDMjFSCzSn085zg1f5mK8M1ZGKrRaY6WWiumhw8i8feA79lSQy sUhhMy8ImxFVUZC8LuSI7gXcMpS3oBuFSXiAZn9lyciUnnU/LiwAwtx+WXfwVetB +GKFI4K0sfw3631hNfX1FWFCfoudsDAelpK8/XP5VbeBRkAyXtYoUl0BDYkvi6XU V5KI7p8OAMSnAly9p/4Fe0ouACqwLPcsQUuo2+nq4++ShwOLosi8g+9rmNQF+edS kikqMdRTARj/mm3DIX15fsJue7mG6bBwaQCIao3OueFW4RPXgBd6XjteEPDdcX4H lw1ZnP93gxo= =dQOt -----END PGP SIGNATURE-----