Cisco Closes Door on VPN DoS

Cisco has announced patches for a potential DoS vulnerability in its VPN gear.

By Michael Hall | Posted Jan 30, 2006
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Cisco has announced that a vulnerability in some of its VPN hardware has been patched.

On Friday afternoon, the company posted a security advisory noting that its Cisco VPN 3000 series concentrators are vulnerable to a denial of service attack (DoS).

The vulnerability affects only concentrator models 3005, 3015, 3020, 3030, 3060, and 3080; running software 4.7.0 through 4.7.2.A. Additionally, since the vulnerability is particular to the series's HTTP service, it affects only those devices with the service enabled. The HTTP service is enabled by default in the affected devices.

According to the company's advisory, sending a crafted packet to one of the affected devices port 80 could cause it to reload and drop connections, with repeated exploits eventually causing a sustained denial of service.

Cisco said it has posted patches, and that workarounds exist. Replacing use of the HTTP service with the HTTPS service, for instance, will mitigate the vulnerability. The company also recommended protecting devices through the use of infrastructure access control lists (ACLs).

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