ASA 5510 Nessus Scan Finds Multiple BSD ipfw / ip6fw ECE Bit Filtering Evasion Vulnerability

[john.mendez]

A 3rd party runs a Nessus scan against our public IP addresses.  They found the Multiple BSD ipfw/ip6fw ECE Bit Filtering Evasion vulnerability on the public IP address of our ASA 5510. 

Does this sound right?  Is there a specific patch I can apply to the ASA to remove the vulnerability?

Thank you,

Cisco Adaptive Security Appliance Software Version 7.2(2), Device Manager Version 5.2(2)

Hardware: ASA5510, 256 MB RAM, CPU Pentium 4 Celeron 1600 MHz

Multiple BSD ipfw / ip6fw ECE Bit Filtering Evasion

Description

The remote host seems vulnerable to a bug wherein a remote attacker can circumvent the firewall by setting the ECE bit within the TCP flags field. At least one firewall (ipfw) is known to exhibit this sort of behavior.

Known vulnerable systems include all FreeBSD 3.x ,4.x, 3.5-STABLE, and 4.2-STABLE.

Solution

If you are running FreeBSD 3.X, 4.x, 3.5-STABLE, 4.2-STABLE, upgrade your firewall. If you are not running FreeBSD, contact your firewall vendor for a patch.

[Marvin Rhoads]

A quick bug search didn't reveal any public-facing bugs or PSIRTs for that issue.

I haven't seen that particular one come up before but I'm surprised that's all they found - your ASA code is something like 6 years old.

There are dozens of later releases with lots of patches - even for your now-end-of-sales ASA 5510. Since your organization hasn't upgraded in over 6 years I'm guessing you don't have support?