[CentOS] UDP Constant IP Identification Field Fingerprinting Vulnerability

Sun Jun 26 20:50:18 UTC 2016
James B. Byrne <byrnejb at harte-lyne.ca>

On Fri, June 24, 2016 12:24, John R Pierce wrote:
> On 6/24/2016 9:20 AM, James B. Byrne wrote:
>> We received a notice from our pci-dss auditors respecting this:
>> CVE-2002-0510 The UDP implementation in Linux 2.4.x kernels keeps
>> the
>> IP Identification field at 0 for all non-fragmented packets, which
>> could allow remote attackers to determine that a target system is
>> running Linux.
> 2.4 kernels are kinda old.   kinda really really old.    are you still
> running CentOS 4 on PCI audited systems ?!??

The CVE is from 2002 and the kernel mentioned refers to the original
report.  Linux core team said it was a non-problem and the issue
remains in the kernel found in CentOS-6.8.  Possibly the one in 7.
Perhaps it is still present in the development branch.

However, all I am seeking is knowledge on how to handle this using
iptables.  I am sure that this defect/anomaly has already been solved
wherever it is an issue.  Does anyone have an example on how to do

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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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