Ubuntu
netcfg package

ubuntu causes DHCP DOS attack during install

Bug #1292019 reported by steverweber
12
This bug affects 2 people
Affects Status Importance Assigned to Milestone
netcfg (Ubuntu)
Confirmed
Undecided
Unassigned

Bug Description

While installing ubuntu server 14.4 or older version 13 we have an DOS on DHCP

During the install at the detect network IP using DHCP we have had issues where if this process is left on this screen overnight we have about 10 million DHCP request/decline events. (a request every ~4ms)

1. click detect IP using DHCP... the bar goes across the screen then gives up...
2. leave the installer at the screen [retry network detection].
3. /detection seems to still continue in a background process/

This is extremely aggressive on our network.

Please have someone look into this before the LTS release.

Thanks.

See original description
steverweber (steve-r-weber)
description: updated
description: updated
description: updated
Seth Arnold (seth-arnold)
information type: Private Security → Public Security
Stéphane Graber (stgraber)
affects: ubuntu → netcfg (Ubuntu)
Jamie Strandboge (jdstrand)
information type: Public Security → Public
Revision history for this message
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in netcfg (Ubuntu):
status: New → Confirmed
Revision history for this message
Jeremiah Bailey (jeremiah-bailey) wrote :

This also affects me, I tried with Ubuntu server iso as well as the netboot tarball. I have tried using an automated install via preseed as well as KS and a manual install just loading the kernel and initrd via tftp. ALL of these methods result in a loop where the client receives a DHCPOFFER from the server(which in my case is our network firewall), this is then followed by a DHCPACK, then the client DHCPDECLINES and keeps looping through all available DHCP addresses in the pool until the DHCP server has no more addresses to give out.

There appears to be an old similar bug here: https://bugs.launchpad.net/ubuntu/+source/netcfg/+bug/848072

Is anyone able to look into this? I have been beating my head against the wall for about a week now and could really use some assistance.

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