Two vulnerabilities have been reported in Cisco VPN 3000 Concentrator, which can be exploited by malicious people to cause a DoS (Denial of Service).

1) An error exists when processing HTTP packets and can be exploited to cause the network device to halt and drop established user connections by sending about 40 specially crafted HTTP packet to the concentrator.

Successful exploitation requires that the HTTP service is enabled (default setting) and may disable the network device requiring a reboot to regain functionality.

According to the vendor, the vulnerability affects software versions 4.7.0 through 4.7.2.A (including version 4.7REL). The discoverer of the vulnerability also reports the vulnerability in version 4.7.2.B. Software versions prior to 4.7.x are not affected.

2) An error exists within the management of TCP connections to port 80. This can be exploited to cause the device to stall and drop user connections by consuming large amount of memory and other resources via multiple open connections.

The vulnerability has been reported in software versions 4.1.x and 4.7.x. Software versions prior to 4.1.x are not affected.

Solution
Update to software version 4.1.7.L or 4.7.2.F.
Further details available to Secunia VIM customers

Provided and/or discovered by
1) Eldon Sprickerhoff, eSentire Inc.
2) Reported by vendor.

Changelog
Further details available to Secunia VIM customers

Original Advisory
Cisco:
http://www.cisco.com/warp/public/707/cisco-sa-20060126-vpn.shtml

eSentire:
http://www.esentire.com/news/vuln-cisco-vpn.html

Deep Links
Links available to Secunia VIM customers