![](https://tools.cisco.com/security/center/images/blue-square.png)
AV:R/AC:L/Au:NR/C:N/I:N/A:C/B:N/E:F/RL:O/RC:C
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Cisco Firewall Services Module versions versions prior to 3.1(3.11) contain a vulnerability that could allow an unauthenticated, remote attacker to create a denial of service (DoS) condition.
The vulnerability is due to an error when the embedded HTTPS server handles certain types of requests. An unauthenticated, remote attacker could exploit this vulnerability by submitting crafted HTTPS request directly to the Cisco Firewall Services Module. This action could cause the device to reload, resulting in a temporary DoS condition.
Cisco has confirmed this vulnerability with a security advisory and released updated software.
A successful attack allows the attacker to cause the Cisco Firewall Services Module to reload. The device will automatically restart, allowing the attacker to cause only a temporary DoS condition. Because the vulnerability requires a malformed HTTPS request, a custom application will be required to exploit the vulnerability. This makes it unlikely that a standard web browser can be utilized.
This vulnerability may also be accidentally exploited by legitimate traffic from a third-party vulnerability scanner.
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Cisco has released a security advisory to address Cisco bug ID CSCsf29974 at the following link: cisco-sa-20070214-fwsm
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Administrators are advised to apply the appropriate patch.
Administrators are advised to restrict access to affected systems.
Administrators are advised to only expose the web administrative interface to management networks.
Administrators are advised to restrict access to the web administrative interface via IP-based ACLs.
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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 tac@cisco.com.
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Version Description Section Status Date 1.0 Initial Release NA Final 2007-Feb-14
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