Disable TCP 1323 Timestamp response through Palo Alto Firewall?

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Disable TCP 1323 Timestamp response through Palo Alto Firewall?

L0 Member

Hi,

I'm wondering whether is there a way to set the PAN Firewall to detect and drop TCP 1323 Timestamp queries to servers?

According to some web vulnerabilities scanning reports, it is reccomended to disable the TCP Timestamp as it discloses server uptime information, allowing attackers to guess the OS patch status.

In the recent Windows server OS (2008 and R2), disabling the TCP1323opts in registry doesn't seem to disable to the Timestamp responses as nmap scan test will still be able to get the uptime information.

In some web scanner reports, there are reccomendations to set in cisco firewalls to disable tcp timestamp eg, (no ip tcp timestamp).

Appreciate the reponse,

Regards,

Hans

7 REPLIES 7

L6 Presenter

Not that im aware of.

Disabling timestamps should be done at the endpoints if you want to block timestamp information.

Easy to do in a linuxbox:

echo "0" > /proc/sys/net/ipv4/tcp_timestamps

Did you reboot your windowsbox before you did the new nmap test?

Also verify with pcap so the uptime which nmap picks up isnt from some application running on your server.

The "no ip tcp timestamp" is usually for traffic that the cisco device itself generates (such as stuff from its mgmt-interface etc) and not for traffic that passes through.

However note that timestamps are part of "high performance tcp" if I remember it correctly so disabling timestamps could in some situations be bad (http://www.ietf.org/rfc/rfc1323.txt).

Also instead of altering the registry try to use this cmdline instead:

netsh int tcp set global timestamps=disabled


http://technet.microsoft.com/en-us/library/cc731258%28WS.10%29.aspx#BKMK_6

You might need a reboot afterwards aswell...

L1 Bithead

Interestingly, for me it is the PALO ALTO 5200 series Vers 8.1 that IS RESPONDING to timestamp requests from a desktop.

Why? I don't know.  Why offer discovery information that a hacker could use?  We have PING enabled on the interface--but I don't see any way to stop it from answering these esoteric ICMP queries.

It is also being asked for ADDRESS MASK (ICMP), but at least it doesn't respond to that.

Hi All,

 

It is possible to drop packets with the timestamp option set through a Zone Protection profile.

 

Network -> Zone Protection -> Packet Based Attack Protection -> IP Drop -> Timestamp.

 

The zone protection profile would then be applied to the ingress zone, untrust.

 

Cheers,

Luke.

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